Wellcome!

 

 

Asked/Added Questions From NCERT: Physics


Question 1. Asked on :25 November 2020:01:26:40 PM

 Why do we dissolve oleic acid in alcohal?

-Added by Himanshi Verma Physics » Motion In A Straight Line.

Answer:

Himanshi Verma

 Oleic acid is soluble in alcohal and diluting it with alcohal will replace it's concentration consequently it will helps to form a very thin (almost the molecular thickness) get formed and we can measure it's thickness by calculating volume.

-Answered by Himanshi Verma On 25 November 2020:01:28:10 PM


Question 2. Asked on :25 November 2020:01:22:49 PM

 What is accuracy and precision?

-Added by Himanshi Verma Physics » Motion In A Straight Line.

Answer:

Himanshi Verma

 Accuracy :- Accuracy is how close a measured value is to the actual value.

Precision:- Precision is how closed the measured value are to each other.

-Answered by Himanshi Verma On 25 November 2020:01:24:02 PM


Question 3. Asked on :25 November 2020:01:21:18 PM

 Name two phyiscal quantities that have units but no dimensional formula?

-Added by Himanshi Verma Physics » Motion In A Straight Line.

Answer:

Shruti Srivastva
Plane Angle and Angular Displacement.

-Answered by Shruti Srivastva On 13 April 2021:01:00:48 PM


Question 4. Asked on :25 November 2020:01:18:43 PM

 Define negative acceleration?

-Added by Himanshi Verma Physics » Motion In A Straight Line.

Answer:

Himanshi Verma

 If the velocity of a body is decreasing with time then it is said to travel with a negative acceleration. {Retardation, declaration}.

-Answered by Himanshi Verma On 25 November 2020:01:19:28 PM


Question 5. Asked on :25 November 2020:01:15:34 PM

 A ball is thrown vertically upwards. What is it's velocity at the highest point?

-Added by Himanshi Verma Physics » Motion In A Straight Line.

Answer:

Himanshi Verma

 It continuous upwards unit it reaches a certain position, and then it falls downwards, At that highest point, it's velocity is instantaneously zero.

-Answered by Himanshi Verma On 25 November 2020:01:16:54 PM


Question 6. Asked on :25 November 2020:01:13:41 PM

 What is Unit vector?

-Added by Himanshi Verma Physics » Motion In A Plane

Answer:

Himanshi Verma

 A unit vector is a vector that has a magnitude of 1 unit. A unit vector is also known as direction vector.

-Answered by Himanshi Verma On 25 November 2020:01:14:31 PM


Question 7. Asked on :25 November 2020:01:09:39 PM

 State the Triangular law of vector addition.

-Added by Himanshi Verma Physics » Motion In A Straight Line

Answer:

Himanshi Verma

 It states that if two vectors acting on a particle at the same time are represented in magnitude and direction by the two sides  of a triangle in one order, their resultant vector is represented in magnitude and direction by the third side of the triangle taken in opposite order.

-Answered by Himanshi Verma On 25 November 2020:01:11:05 PM


Question 8. Asked on :25 November 2020:01:04:53 PM

 What is instantaneous speed and velocity?

-Added by Himanshi Verma Physics » Motion In A Straight Line

Answer:

Himanshi Verma

 Instantaneous speed = The speed of a body at a particular instant of time during the motion is called instantaneous speed.

Instantaneous velocity = The velocity of a body at any instant of time is known as instantaneous velocity.

-Answered by Himanshi Verma On 25 November 2020:01:05:35 PM


Question 9. Asked on :25 November 2020:01:02:09 PM

Define Average speed

-Added by Himanshi Verma Physics » Motion In A Straight Line

Answer:

Himanshi Verma

 The average distance covered by a body per unit time is known as average speed. It is calculated as the ratio of the total distance travelled to the total time taken.

-Answered by Himanshi Verma On 25 November 2020:01:03:26 PM


Question 10. Asked on :25 November 2020:12:58:46 PM

 What is Homogeneity Principle?

-Added by Himanshi Verma Physics » Units And Measurements

Answer:

Himanshi Verma

 If the dimensions of the left hand side of an equation are equal to the dimensions of right hand side of the equation is dimensionally correct. this is known as Homogeneity Principle. 

-Answered by Himanshi Verma On 25 November 2020:01:00:47 PM


Question 11. Asked on :25 November 2020:12:56:13 PM

Name four fundamental forces in nature?

-Added by Himanshi Verma Physics » Phyiscal World

Answer:

Himanshi Verma

 Four fundamental forces in nature are:-

1) Gravitational force

2) Electromagnetic force

3) Weak nuclear force 

4) Strong nuclear force

-Answered by Himanshi Verma On 25 November 2020:12:57:38 PM


Question 12. Asked on :29 October 2020:07:55:04 PM

 full form of AME? 

-Added by Master Purushottam Physics » G.K

Answer:

Anjali Kumari
Aircraft Maintenance Engineering 

-Answered by Anjali Kumari On 15 November 2020:07:31:17 PM


Question 13. Asked on :08 October 2020:06:03:11 PM

Can a kitchen be cooled by leaving the door of an electric refrigerator open? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
No, a kitchen cannot be cooled by leaving the door of the refrigerator open.

-Answered by Shruti Srivastva On 08 October 2020:06:04:12 PM


Question 14. Asked on :08 October 2020:06:01:44 PM

Is it theoretically possible to device a heat engine which will create no thermal pollution? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
No.

-Answered by Shruti Srivastva On 08 October 2020:06:02:50 PM


Question 15. Asked on :08 October 2020:05:59:50 PM

The temperature of the surface of the sun is approximately 6000 K. If we take a big lens and focus the sun rays, can we produce a temperature of 8000K? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
No.

-Answered by Shruti Srivastva On 08 October 2020:06:01:26 PM


Question 16. Asked on :08 October 2020:05:40:37 PM

Why can a ship not use the internal energy of sea water to operate its engine? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
For the operation of a heat engine we require a sink at temperature lower than the source and of sufficiently high thermal capacity, which is not possible in the sea. 

-Answered by Shruti Srivastva On 08 October 2020:05:41:51 PM


Question 17. Asked on :08 October 2020:05:39:45 PM

What is the conversion o heat into work not possible without sink at lower temperatures? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Anjali Kumari

 For converting heat energy into work continuosly, a part of heat energy absorbed from the source has to be rejected. The heat energy can be rejected only if there is a body, whose temperature is less than that of the source. This body at lower temperature is the sink.

-Answered by Anjali Kumari On 09 October 2020:06:59:06 PM


Question 18. Asked on :08 October 2020:05:39:07 PM

What is the differences between heat and work? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Anjali Kumari

 Heat and work are two different ways of transferring energy from one system to another. The the distinction between Heat and Work is important in the field of thermodynamics. Heat is the transfer of thermal energy between systems, while work is the transfer of mechanical energy between two systems.

-Answered by Anjali Kumari On 09 October 2020:06:49:55 PM


Question 19. Asked on :08 October 2020:05:37:31 PM

By what method can the internal energy of an ideal gas be changed? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
By heating or cooling.  

-Answered by Shruti Srivastva On 08 October 2020:05:38:36 PM


Question 20. Asked on :08 October 2020:05:36:12 PM

A liquid is being converted into steam at its boiling point. What will be the specific heat of the liquid at this time? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Anjali Kumari

 When liquid is converted into steam at its boling point, the temperature of liquid remains constant. i.e., change in temperature ΔT=0. Hence the specific heat, s=ΔQmΔT=ΔQm×0=∞

-Answered by Anjali Kumari On 09 October 2020:07:01:01 PM


Question 21. Asked on :08 October 2020:05:35:24 PM

What is the specific heat of a gas in an adiabatic process?

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Anjali Kumari

 The specific heat of a gas in an adiabatic process is zero but it is infinite in an isothermal process

-Answered by Anjali Kumari On 09 October 2020:06:52:17 PM


Question 22. Asked on :08 October 2020:05:34:20 PM

What is the specific heat of a gas in an isothermal process? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Anjali Kumari
The specific heat capacity of an ideal gas for isothermal process is infinity.

-Answered by Anjali Kumari On 09 October 2020:07:02:09 PM


Question 23. Asked on :08 October 2020:05:33:26 PM

A gas has a two principal specific heats. Which one is greater and why? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Anjali Kumari
specific heat at constant pressure is more than the specific heat at constant volume because the gas can expand in the first case, causing more absorption of heat as compared to other one.

-Answered by Anjali Kumari On 09 October 2020:07:04:21 PM


Question 24. Asked on :08 October 2020:05:32:40 PM

Why a gas has two principal specific heat capacities? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Anjali Kumari
Gas has two specific heat capacities because it has two variables pressure and volume sensitive. ... If volume of the gas is constant and heat is supplied. Then we define specific heat is called specific heat at constant volume (CV). Similarly at constant pressure specific heat capacity is defined as (CP).

-Answered by Anjali Kumari On 09 October 2020:07:07:26 PM


Question 25. Asked on :08 October 2020:05:31:40 PM

How many specific heats does a gas possess?

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Anjali Kumari

 The specific heats of gases are given as Cp and Cv at constant pressure and constant volume respectively while solids and liquids are having only single value for specific heat.

-Answered by Anjali Kumari On 09 October 2020:07:09:22 PM


Question 26. Asked on :08 October 2020:05:30:18 PM

Can the work done during a cyclic process be zero? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
Yes. 

-Answered by Shruti Srivastva On 08 October 2020:05:31:12 PM


Question 27. Asked on :08 October 2020:05:28:47 PM

What is the significance of the area  of closed curve on a P-V diagram? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
The area gives the work done in a cyclic process.

-Answered by Shruti Srivastva On 08 October 2020:05:29:49 PM


Question 28. Asked on :08 October 2020:05:25:10 PM

Can two isothermal curves intersect? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
No.

-Answered by Shruti Srivastva On 08 October 2020:05:26:11 PM


Question 29. Asked on :08 October 2020:04:10:58 PM

Is the equation PV=RT valid for isothermal and adiabatic processes? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
Yes.

-Answered by Shruti Srivastva On 08 October 2020:04:12:56 PM


Question 30. Asked on :08 October 2020:04:09:10 PM

Whose molecules : liquid water at 0°C or ice at 0°C have greater potential energy? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
Water molecule.

-Answered by Shruti Srivastva On 08 October 2020:04:10:40 PM


Question 31. Asked on :08 October 2020:04:08:20 PM

Why does air pressure in a car tyre increased during driving?

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Anjali Kumari
During driving, temperature of air inside increases while its volume remains constant. According to Charle's law, at constant volume V,P∝T. Therefore, pressure of air inside the tyre increases.

-Answered by Anjali Kumari On 09 October 2020:07:10:59 PM


Question 32. Asked on :08 October 2020:04:07:19 PM

Can the temperature of a gas be increased by keeping its pressure and volume constant? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
No.

-Answered by Shruti Srivastva On 08 October 2020:04:08:10 PM


Question 33. Asked on :08 October 2020:04:05:11 PM

 Is it possible that there is no increase in the temperature of a body despite being heated?

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
Yes.

-Answered by Shruti Srivastva On 08 October 2020:04:07:08 PM


Question 34. Asked on :07 October 2020:06:06:26 PM

Is it possible that there is change in temperature of a bdy without giving heat ti it or taking heat from it? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
Yes.

-Answered by Shruti Srivastva On 07 October 2020:06:07:22 PM


Question 35. Asked on :07 October 2020:06:04:57 PM

Is it possible that there is change in temperaure of a body without giving heat to it or taking heat from it? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Anjali Kumari
Yes, for example in an adiabatic compression, temperature rises and in an adiabatic expansion, temperature falls, although no heat is given or taken from the system in the repective changes.

-Answered by Anjali Kumari On 09 October 2020:07:12:05 PM


Question 36. Asked on :07 October 2020:06:01:58 PM

When a gas is suddenly compressed, its temperature rises. Why? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
Sudden compression of a gas is an adiabatic process. The work done in compressing the gas increaces the internal energy of the gas. Hence the temperature of the gas rises.

-Answered by Shruti Srivastva On 07 October 2020:06:03:10 PM


Question 37. Asked on :07 October 2020:05:59:47 PM

Cooling is produced when a gas at high pressure suddenly expands. Why?

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
During its expansion the gas does work against high pressure. This decreaces the internal energy and hence the temperature of the gas.

-Answered by Shruti Srivastva On 07 October 2020:06:00:36 PM


Question 38. Asked on :07 October 2020:05:58:10 PM

An ideal gas is coompressed at constant temperature. Will its internal energy increase or decrease?

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
It will remain same.

-Answered by Shruti Srivastva On 07 October 2020:05:59:28 PM


Question 39. Asked on :07 October 2020:05:55:01 PM

When is the heat supplied to a system equal to thev increase in its internal energy?

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Anjali Kumari
Heat supplied to a system is always equal to increase in its internal energy only if there is no external work is done by the system.. So delta V is zero and what you get is no work

-Answered by Anjali Kumari On 09 October 2020:07:15:54 PM


Question 40. Asked on :07 October 2020:05:52:44 PM

Is the internal energy of a gas a function of pressure? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
The internal energy of an ideal gas depemds only on the temperature of the gas, while that of a real gas depends on the temperature and volume, which in turns is dependent on pressure.

-Answered by Shruti Srivastva On 07 October 2020:05:53:20 PM


Question 41. Asked on :07 October 2020:05:50:09 PM

How does the internal energy of an ideal gas differ from that of real gas?

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
The internal energy of an ideal gas consists of only the kinetic energy of the particles. But for real gases it consists of both the kinetic as well as potential energies.

-Answered by Shruti Srivastva On 07 October 2020:05:50:59 PM


Question 42. Asked on :07 October 2020:05:49:19 PM

State the first law of thermodynamic? 

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Anjali Kumari

he first law of thermodynamics is a version of the law of conservation of energy, adapted for thermodynamic processes, distinguishing two kinds of transfer of energy, as heat and as thermodynamic work, and relating them to a function of a body's state, called Internal energy.

The law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another, but can be neither created nor destroyed.

For a thermodynamic process without transfer of matter, the first law is often formulated[1][nb 1]

,

-Answered by Anjali Kumari On 09 October 2020:07:13:18 PM


Question 43. Asked on :07 October 2020:05:45:16 PM

What is a cylic process?

-Added by Shruti Srivastva Physics » Thermodynamics

Answer:

Shruti Srivastva
Any process in which the system returns to its initial state after undergoing a series of changes is known as a cylic process.

-Answered by Shruti Srivastva On 07 October 2020:05:48:05 PM


Question 44. Asked on :07 October 2020:05:43:48 PM

What happens if water vapour at a pressure of 0.004 atm is cooled to 0°C?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

nisha sheikh
 if water vapour at a pressure of 0.003 atmosphere is cooled to 0^(@)C ... The pressure corresponding to triple point of water is 0.46 cm of Hg (=0.006 atm)

-Answered by nisha sheikh On 21 October 2020:06:51:15 PM


Question 45. Asked on :07 October 2020:05:40:35 PM

Are the relative amounts of ice, water and vapour fixed at the triple point of water?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
At the triple point of water the temperature and pressure are fixed. However, the relative amounts of the three phases are not unique. The relative amounts o the three phases can be varied by adding or taking out heat from the system. 

-Answered by Shruti Srivastva On 07 October 2020:05:41:45 PM


Question 46. Asked on :07 October 2020:05:37:14 PM

What is the significance of negative slope of ice line of water? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
It indicates that the melting point if ice decreases with increase in pressure. This is because volume of water on melting is less than the volume of ice.

-Answered by Shruti Srivastva On 07 October 2020:05:38:53 PM


Question 47. Asked on :07 October 2020:05:35:26 PM

What is the temperature above which steam will not condense of water even i it is compressed to very large pressure? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
Above the critical temperature steam will not condens.

-Answered by Shruti Srivastva On 07 October 2020:05:36:33 PM


Question 48. Asked on :07 October 2020:05:33:02 PM

How does the boiling point of water change with pressure? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The boiling point of water increaces with the increase in pressure.

-Answered by Shruti Srivastva On 07 October 2020:05:34:05 PM


Question 49. Asked on :07 October 2020:05:28:44 PM

What is the pressure on melting point of a solid? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The melting point o a soli may increase or decreaces depending on the nature of solid.

-Answered by Shruti Srivastva On 07 October 2020:05:31:57 PM


Question 50. Asked on :06 October 2020:06:07:27 PM

Can a gas be liquified at any temperature by the increase of pressure alone?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
No.

-Answered by Shruti Srivastva On 06 October 2020:06:08:43 PM


Question 51. Asked on :06 October 2020:06:04:56 PM

What is critical temperature? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

nisha sheikh
The critical temperature of a substance is the temperature at and above which vapor of the substance cannot be liquefied, no matter how much pressure is applied. Every substance has a critical temperature

-Answered by nisha sheikh On 07 October 2020:11:01:14 AM


Question 52. Asked on :06 October 2020:06:02:40 PM

In what respect is the respect is the thermal radiation different rom lights? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Anjali Kumari
Thermal radiation are electromagnetic waves having wavelength range from 700 nm to 1 mm. They produce heat when absorbed by a body. They are not visible 

-Answered by Anjali Kumari On 09 October 2020:07:18:55 PM


Question 53. Asked on :06 October 2020:05:59:15 PM

Which object will cool faster when kept in open air, the one at 300°C or the one at 100°C?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
300°C.

-Answered by Shruti Srivastva On 06 October 2020:06:02:04 PM


Question 54. Asked on :06 October 2020:05:58:18 PM

Black body radiation is white. Comment.

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

nisha sheikh
Black-body radiation has a characteristic, continuous frequency spectrum that depends only on the body's temperature, called the Planck spectrum or Planck's law. ... When the body appears white, it is emitting a substantial fraction of its energy as ultraviolet radiation

-Answered by nisha sheikh On 07 October 2020:11:03:27 AM


Question 55. Asked on :06 October 2020:05:56:05 PM

Why is there the word displacement in Wien's displacement law?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
As the temperature is increased, the wavelength having maximum intensity is displaced towards the shoter wavelength region.

-Answered by Shruti Srivastva On 06 October 2020:05:56:56 PM


Question 56. Asked on :06 October 2020:05:52:16 PM

A hole in the cavity of a radiation is a black body. Why?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva

A hole in the cavity of a radiation does not reflect any radiation incident on it. So it is a black body. 

-Answered by Shruti Srivastva On 06 October 2020:05:54:54 PM


Question 57. Asked on :06 October 2020:05:51:00 PM

Why are clear nights colder then cloudy nights?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

nisha sheikh
This is true even during complete overcast conditions because the clouds are generally colder than the air at the ground. Thus clouds in effect reduce the radiation imbalance between the upward flux from the ground and downward flux from the atmosphere, relative to that on clear nights.

-Answered by nisha sheikh On 07 October 2020:11:04:30 AM


Question 58. Asked on :06 October 2020:05:48:39 PM

Is it necessary that all black coloured objects should be considered black bodies?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
No.

-Answered by Shruti Srivastva On 06 October 2020:05:49:47 PM


Question 59. Asked on :06 October 2020:05:46:01 PM

Why does a piece o red glass absorbs green colour strongly. But at higher temperatures, it emits green colour strongly. 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
At low temperatures, the red glass absorbs  green colour strongly. But at higher temperatures, it emits green colour strongly. 

-Answered by Shruti Srivastva On 06 October 2020:05:47:52 PM


Question 60. Asked on :06 October 2020:05:43:35 PM

Why a body with large reflectively is a poor emitter? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
A body whose reflectively is large would naturally absorb less heat. So, a body with large reflectively is a poor emitter.

-Answered by Shruti Srivastva On 06 October 2020:05:44:30 PM


Question 61. Asked on :06 October 2020:05:42:13 PM

Why do animals curl 8 into a ball, when they feel very cold?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

nisha sheikh
Animals curl up into a ball when they're feeling cold in order to minimize the heat loss. The heat from the body of animal will flow towards the cold.

-Answered by nisha sheikh On 07 October 2020:11:06:30 AM


Question 62. Asked on :06 October 2020:05:39:28 PM

Why are the cooling coils fitted near the ceiling of a refrigerator?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
As the air gets cooled in the upper part o refrigerator, it becomes denser and goes down. 

-Answered by Shruti Srivastva On 06 October 2020:05:41:06 PM


Question 63. Asked on :06 October 2020:05:37:27 PM

Water is heated from below. why? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
When water is heated, its density decreases and it rise up. 

-Answered by Shruti Srivastva On 06 October 2020:05:38:13 PM


Question 64. Asked on :06 October 2020:05:35:14 PM

 Can we boil water inside an earth satelite? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter 

Answer:

Shruti Srivastva

 No.

-Answered by Shruti Srivastva On 06 October 2020:05:36:52 PM


Question 65. Asked on :06 October 2020:05:34:19 PM

 Why snow is a better heat insulator than ice? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

nisha sheikh
Snow is better insulator than ice because snow contains air packets inside it and air is a good insulator of heat . Due to this , snow takes longer time to melt than ice of same mass .

-Answered by nisha sheikh On 07 October 2020:11:07:14 AM


Question 66. Asked on :03 October 2020:06:04:38 PM

Why it is much hotter above a fire than by its side? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva

Heat carried away from a fire sideways mainly by radiation. Above the fire, heat is carried by both radiation and convection of air.

-Answered by Shruti Srivastva On 06 October 2020:05:32:45 PM


Question 67. Asked on :03 October 2020:06:03:36 PM

Why rooms are provided with the ventilators near the roof?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
To purify air.

-Answered by Shruti Srivastva On 03 October 2020:06:04:21 PM


Question 68. Asked on :03 October 2020:06:00:55 PM

Why small holes are provided at the bottom of the chimney of the lamp?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The hot air and burnt gases rise upwards through the chimney. Fresh air enters through the holes provided at bottom. In the absence of these holes, convection currents will not be set up and the lamp would go off.

-Answered by Shruti Srivastva On 03 October 2020:06:01:43 PM


Question 69. Asked on :03 October 2020:05:58:43 PM

I air is poor conductor of heat, why do we not feel warm without clothes?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
Althrough air is poor conductor of heat, it carries away heat from body due to convection when we are without clothes. Hence we feel cold.

-Answered by Shruti Srivastva On 03 October 2020:05:59:41 PM


Question 70. Asked on :03 October 2020:05:55:03 PM

Why felt rather than air is employed for thermal insulation?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
Through air is a bad conductor of it, it transfers heat easily by convection. Felt traps air between its fibres and convection currents cannot be set up in it.

-Answered by Shruti Srivastva On 03 October 2020:05:56:08 PM


Question 71. Asked on :03 October 2020:05:52:19 PM

Why do elctrons in insulator or not contribute towards its thermal conductivity? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
Electrons do not have free electrons inside them. So electrons have no contibution towards their thermal conductivity.

-Answered by Shruti Srivastva On 03 October 2020:05:53:30 PM


Question 72. Asked on :03 October 2020:05:49:14 PM

Usually a good conductor of heat is a good conductor of elcectricity also. Give reason?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
Electron contribute largerly both towards the flow of elctricity and the flow of heat. A good conductor cntains a large number of free electrons. So it is both a good conductor o heat and elctricity.

-Answered by Shruti Srivastva On 03 October 2020:05:50:18 PM


Question 73. Asked on :03 October 2020:05:46:42 PM

Stainless steel cooking pans are perferrred with extra copper bottom. Why?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The thermal conductivity of copper is much  larger than that of steel.The copper bottom allows more heat of flow into the pan and hence help in cooking the food faster.

-Answered by Shruti Srivastva On 03 October 2020:05:47:45 PM


Question 74. Asked on :03 October 2020:05:45:43 PM

Why do we use copper gauze in davy's afety lamp?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Anjali Kumari
The final design was very simple: a basic lamp with a wire gauze chimney enclosing the flame. The holes let light pass through, but the metal of the gauze absorbs the heat. The lamp is safe to use because the flame can't heat enough flammable gas to cause an explosion, although the flame itself will change colour.

-Answered by Anjali Kumari On 11 October 2020:02:12:35 PM


Question 75. Asked on :03 October 2020:05:43:15 PM

Woole clthes are warm in winter. Why?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
Woolen fibres enclos a large amount of air in them. Both wool and air are bad conductor of heat. The small coefficient of thermal conductivity prevets the loss of heat from our body due to conduction. S o we feel warm in woolen clothes.

-Answered by Shruti Srivastva On 03 October 2020:05:43:54 PM


Question 76. Asked on :03 October 2020:05:41:08 PM

A piece of wire gauze is placed over the Bunsen burner. If the gas is turned on below the gauge, will the flame go above the gauge?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
Copper is a very good conductor o heat. The copper gauze absorbs most o the heat. 

-Answered by Shruti Srivastva On 03 October 2020:05:42:30 PM


Question 77. Asked on :03 October 2020:05:37:55 PM

Why we can easily boil water in a paper cup?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
This is because heat is easily conducted through the paper to the water, and as such the temperature through the paper to the water, and as such the temperature attained is not sufficient for the paperto be charred.

-Answered by Shruti Srivastva On 03 October 2020:05:38:44 PM


Question 78. Asked on :03 October 2020:05:35:08 PM

When we step barefoot into an ofice with a marble floo, we feel cold. Why? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
This is because marble is a better conductor of heat than concrete. When we walk barefooted on a marble floor, heat flows our body through the feet and we feel cold.

-Answered by Shruti Srivastva On 03 October 2020:05:36:00 PM


Question 79. Asked on :03 October 2020:05:33:33 PM

Calorimeters are made of metals not glass.Why?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
This is because metals are good conductors of heat and have low specific heat capacity.

-Answered by Shruti Srivastva On 03 October 2020:05:34:19 PM


Question 80. Asked on :03 October 2020:05:31:13 PM

A squirrel wraps its bushy tail round its body during its winter sleep.Why?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The bushy tail provides its body a non-conducting blankets. So the loss of heat by conduction is minimised.

-Answered by Shruti Srivastva On 03 October 2020:05:32:27 PM


Question 81. Asked on :03 October 2020:05:28:37 PM

Why are two thin blankets are warmer then a single blanket of double the thickness? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The air enclosed between two blankets prevents the transfer o heat from our body to outside.

-Answered by Shruti Srivastva On 03 October 2020:05:29:33 PM


Question 82. Asked on :03 October 2020:05:24:34 PM

Why birds are often seen to swell their feathers in winter?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
When the birds swell there fether, they are able to enclose air in the feathers.

-Answered by Shruti Srivastva On 03 October 2020:05:25:25 PM


Question 83. Asked on :02 October 2020:06:28:37 PM

Why do metal utensils have wooden handles? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
Because wood is a bad conductor of heat.

-Answered by Shruti Srivastva On 02 October 2020:06:29:20 PM


Question 84. Asked on :02 October 2020:06:25:57 PM

What kind of thermal conductivity and specific heat requirments would you specify for cooking utensils?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
A cooking utensils should have high conductivity so that it can conduct heat through itself and transfer it to the contents quickly.

-Answered by Shruti Srivastva On 02 October 2020:06:27:12 PM


Question 85. Asked on :02 October 2020:06:24:08 PM

Why is water used as an eective coolant?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The specific heat of water is very high. When it runs over hot parts of an engine or machinery, it absorbs a large amount of heat.

-Answered by Shruti Srivastva On 02 October 2020:06:24:46 PM


Question 86. Asked on :02 October 2020:06:22:40 PM

Why juice bottles are placed under water in the cold countries? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
This is done so to prevent the freezing of juice.

-Answered by Shruti Srivastva On 02 October 2020:06:23:33 PM


Question 87. Asked on :02 October 2020:06:20:48 PM

Why water is preffered to any other liquid in the hot water bottles? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva

water is preffered to any other liquid in the hot water bottles because due to high specific heat is does not cool fast. Also for the given mass of water. 

-Answered by Shruti Srivastva On 02 October 2020:06:21:37 PM


Question 88. Asked on :02 October 2020:06:18:38 PM

What is the differences between the specific heat and the molar specific heat?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The specific heat is the heat capacity per unit mass whereas the molar specific heat is the heat capacity per mole.

-Answered by Shruti Srivastva On 02 October 2020:06:19:35 PM


Question 89. Asked on :02 October 2020:06:15:38 PM

Give an example of a system in which no heat s transferred to or from a system but the temperature of the system changes.

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
When a paddle wheel arrangement is worked while dipping in water, the temperature of water increaces without any addition of heat.

-Answered by Shruti Srivastva On 02 October 2020:06:17:21 PM


Question 90. Asked on :02 October 2020:06:13:04 PM

If an elctric fan be switched in a closed room, will the air of the room be cooled? If not, why do we feel cold?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The air will not be cooled. In fact, it will get heated up due to the increase in the speed o its molecules. we feel cold due to faster evaporation of sweat.

-Answered by Shruti Srivastva On 02 October 2020:06:14:18 PM


Question 91. Asked on :02 October 2020:06:10:46 PM

A match stick can be lighted by rubbing it against a rough surface. Why?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
When the match stick is rubbed against a rough surace , work is done against friction. This work done appears as heat and lights up the match stick.

-Answered by Shruti Srivastva On 02 October 2020:06:11:51 PM


Question 92. Asked on :02 October 2020:06:09:45 PM

Can a given amount of mechanical energy be completely converted into heat?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
Yes.

-Answered by Shruti Srivastva On 02 October 2020:06:10:35 PM


Question 93. Asked on :02 October 2020:06:05:32 PM

Why do the brake drums of a car get heated, when the car moves down a hill at a constant speed? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
As the car moves down a hill at constant speed, its kinetic energy does not change. But its gravitational potential energy constantly decreaces, which gets converted into heat and so the brake drums get heated.

-Answered by Shruti Srivastva On 02 October 2020:06:06:28 PM


Question 94. Asked on :02 October 2020:06:02:25 PM

There is a slight temperature differnces between the water all at the top and the bottom. Why?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The potential energy of water at the top of the fall gets converted into heat kinetic energy at the bottom of the fall. When water hite=s the ground, a part of its kinetic energy gets converted into heat which increaces its temperature slightly.

-Answered by Shruti Srivastva On 02 October 2020:06:03:23 PM


Question 95. Asked on :02 October 2020:05:59:10 PM

When we rub oue hands, they are warmed but only to a certain maximum temperature. Why?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The work done in rubbing is converted into heat. But ater some time when the temperature of the hand is raised, the total heat produced goes into the atmosphere.

-Answered by Shruti Srivastva On 02 October 2020:06:00:39 PM


Question 96. Asked on :02 October 2020:05:56:38 PM

A thermous bottle containing water is vigorously shaken. What will be theeffect on the temperature of water?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The temperature of the water will increaces slightly. This is because some o the work done against opposing viscous force will be converted into heat.

-Answered by Shruti Srivastva On 02 October 2020:05:57:52 PM


Question 97. Asked on :02 October 2020:05:54:43 PM

Why is J called a converter factor?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
Because it help us to convert work measured in terms of joules into heat expressed in calories or vice-versa.

-Answered by Shruti Srivastva On 02 October 2020:05:55:23 PM


Question 98. Asked on :02 October 2020:05:53:38 PM

Is J a physical quantity?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
No.

-Answered by Shruti Srivastva On 02 October 2020:05:54:21 PM


Question 99. Asked on :02 October 2020:05:49:32 PM

Explain why a beaker filled with water a 4ºC overflows if the temperarure is decreased or increased?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
It is because of the anamalous expansion o water. Water has a maximum density at 4°C. Therefore, water expands wheter it is heated above 4°C or cooled below 4°C.

-Answered by Shruti Srivastva On 02 October 2020:05:51:20 PM


Question 100. Asked on :02 October 2020:05:46:39 PM

How does the diameter of the opening in the cast iron plate of a kitchen stove change, when the stove is heated?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The opening in the stove is circular. But its diameter undergoes linear expansion on heating.

-Answered by Shruti Srivastva On 02 October 2020:05:48:17 PM


Question 101. Asked on :30 September 2020:06:17:30 PM

In riveting boiler plates, red hot riverts are used. Why?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
Red hot revets are used so that on cooling, the grip becomes firm and steam tight.

-Answered by Shruti Srivastva On 30 September 2020:06:18:23 PM


Question 102. Asked on :30 September 2020:06:16:32 PM

Why iron rims are heated red hot before being put on the cart wheels?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Anjali Kumari
The iron ring to be put on the rim of a cart wheel is always of slightly smaller diameter than that of the wheel. When the iron ring is heated to become red hot, it expands and slips on to the wheel easily. When it is cooled, it contracts and grips the wheel firmly.

-Answered by Anjali Kumari On 11 October 2020:02:07:50 PM


Question 103. Asked on :30 September 2020:06:14:26 PM

Thick bottomed drinking glasses frequently crack if hot water poured into them. Why?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
Glass is bad conductor of heat. It does not pass down the heat quickly to the lower surface. 

-Answered by Shruti Srivastva On 30 September 2020:06:15:36 PM


Question 104. Asked on :30 September 2020:06:12:19 PM

A tightened glass stopper can be taken out easily by pouring hot water around the neck o the bottle. Why?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The neck expands but not the stopper due to poor conductivity of glass. Thus the stopper can be taken out easily.

-Answered by Shruti Srivastva On 30 September 2020:06:13:27 PM


Question 105. Asked on :30 September 2020:06:09:37 PM

A brass disc fits snugly in a hole in a steel plate. Should we heat or cool the system to loosen the disc from the hole?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
a brass is greter than that or steel. On cooling, the disc shrinks to a grater extent than the hole, and hence the disc would get loosened.

-Answered by Shruti Srivastva On 30 September 2020:06:11:06 PM


Question 106. Asked on :30 September 2020:06:07:05 PM

Why must telephone or power lines necessarily slag a little?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
This slag is allow for contradiction in winter. If no sag is allowed, the wire may snap in extremely cold weather.

-Answered by Shruti Srivastva On 30 September 2020:06:08:09 PM


Question 107. Asked on :30 September 2020:06:04:35 PM

Why are loops provided in long metal pipes used for cappying oil and any other liquid over long distances?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The loops in metal pipes are provided in order to avoid the strain that would develop in the pipes when the temperature changes and hence the pressure of liquids in them changes.

-Answered by Shruti Srivastva On 30 September 2020:06:05:44 PM


Question 108. Asked on :30 September 2020:06:02:41 PM

Why a small gap is left between the iron rails of railway tracks?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
If no gap is let between the iron rails, the rails may bend due to expansion in summer and the train may get derailed.

-Answered by Shruti Srivastva On 30 September 2020:06:03:32 PM


Question 109. Asked on :30 September 2020:06:01:42 PM

Is the temperature coeficient always positive?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
No.

-Answered by Shruti Srivastva On 30 September 2020:06:02:24 PM


Question 110. Asked on :30 September 2020:05:59:18 PM

Why does a solid expand on heating?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The average distance between the positions of equillibrium of the atoms of a solid increaces with an increase in temperature which results in the thermal expansion of a solid.

-Answered by Shruti Srivastva On 30 September 2020:06:00:05 PM


Question 111. Asked on :30 September 2020:05:57:34 PM

Do all solids expand on hetaing?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
No.

-Answered by Shruti Srivastva On 30 September 2020:05:59:02 PM


Question 112. Asked on :30 September 2020:05:55:32 PM

A body at higher temperature contains moer heat, comment.

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The statement is not always true.The heat content of a body depends upon its mass, specific heat and temperature.

-Answered by Shruti Srivastva On 30 September 2020:05:56:22 PM


Question 113. Asked on :30 September 2020:05:52:41 PM

Why is a constant volume gas thermometer preffered as a standard thermometer than a constant pressure gas thermometer?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
This is because the changes in pressure can be measured with greater accuracy than changes in volume.

-Answered by Shruti Srivastva On 30 September 2020:05:54:27 PM


Question 114. Asked on :30 September 2020:05:50:27 PM

Why the temperature above 1200ºC cannot be measured accurately by a platinum resistance thermometer?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
This is because platinum begins to evaporation above 1200ºC.

-Answered by Shruti Srivastva On 30 September 2020:05:51:45 PM


Question 115. Asked on :30 September 2020:05:46:54 PM

Mercury boils at 357ºC. How can then a mercury thermometer be used to measure temperature upto 500ºC?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The space above the mercury is filled with nitrogen. This increaces the boling point of mercury and raises the upper limit of the mercury thermometer.

-Answered by Shruti Srivastva On 30 September 2020:05:48:42 PM


Question 116. Asked on :30 September 2020:05:45:40 PM

Can the temperature of a body be negative on the kelvin scale?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva

No. 

-Answered by Shruti Srivastva On 30 September 2020:05:46:31 PM


Question 117. Asked on :30 September 2020:05:43:53 PM

Why are gas thermometers are more sensitive than mercury thermometers?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The coefficient of expansion of a gas is very large as compared to the coeicient of expansion o mercury. 

-Answered by Shruti Srivastva On 30 September 2020:05:44:36 PM


Question 118. Asked on :30 September 2020:05:41:44 PM

What do you mean by triple point of water? Why it is unique?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
It is the temperature at which the three phases of water: ice, liquid, and water vapour are equally stable and exsist simultaneously. 

-Answered by Shruti Srivastva On 30 September 2020:05:42:38 PM


Question 119. Asked on :30 September 2020:05:38:33 PM

Why should a thermometer bulb have a small heat capacity? 

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
Because it absorb less heat from the body whose temperature s to be measured. Hence the temperature of that body will practically unchanged. 

-Answered by Shruti Srivastva On 30 September 2020:05:40:14 PM


Question 120. Asked on :26 September 2020:06:11:42 PM

Why a clinical thermometer should not be sterilized by boiling?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
The range of clinical thermometer is usually from 95º to 110ºF and the boiling point of water is 212º . 

-Answered by Shruti Srivastva On 26 September 2020:06:12:56 PM


Question 121. Asked on :26 September 2020:06:08:59 PM

What is dynamical theory of water?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
According to dynamical theory, the amount of heat possessed by a body is equal to the total kinetic energy o ots molecules and its temperature is proportional to the average kinetic energy of its molecules.

-Answered by Shruti Srivastva On 26 September 2020:06:09:50 PM


Question 122. Asked on :26 September 2020:06:07:06 PM

Is temperature a macroscopic or microscopic concept?

-Added by Shruti Srivastva Physics » Thermal Properties Of Matter

Answer:

Shruti Srivastva
Temperatue is macroscopic concept.

-Answered by Shruti Srivastva On 26 September 2020:06:08:24 PM


Question 123. Asked on :26 September 2020:06:02:58 PM

Explain why some  oils spred on water, when other float as drops.

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Isf surace tension of oil is less than that of water, then it spread on water.

-Answered by Shruti Srivastva On 26 September 2020:06:04:16 PM


Question 124. Asked on :26 September 2020:05:59:54 PM

Water gets depressed in a glass tube whose surface is coated with wax. Why?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The angle of contact between water and wax is obtuse. So cos Θ is negative and hence cappilary rise.

-Answered by Shruti Srivastva On 26 September 2020:06:01:15 PM


Question 125. Asked on :26 September 2020:05:57:46 PM

 The split in the tip o the nib acts as a capillary tube. The ink rises up in the nib due to capillary action. Hence we are able to write with the pen.

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

nisha sheikh
The tip of the nib of a pen is split in order to provide a capillary which helps the ink to rise to the end of the nib and enables it to write continuously.

-Answered by nisha sheikh On 22 October 2020:06:37:45 PM


Question 126. Asked on :26 September 2020:05:56:04 PM

Why new earthen pots keep water cooler than the older one? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Due to cappilary action.

-Answered by Shruti Srivastva On 26 September 2020:05:57:04 PM


Question 127. Asked on :26 September 2020:05:54:06 PM

A piece of chalk immersed in water emits bubble in all directions why?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Because it has a large number of cappilaries.

-Answered by Shruti Srivastva On 26 September 2020:05:55:36 PM


Question 128. Asked on :26 September 2020:05:51:56 PM

Why undergarment are usually made of cotton? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Cotton threads have large number of cappilaries between them. These capillaries help to absorb sweat from the surface of the body due to capillaries action.

-Answered by Shruti Srivastva On 26 September 2020:05:52:32 PM


Question 129. Asked on :26 September 2020:05:49:32 PM

Why sand is drier than clay?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Due to narrow pores in clay, water rises in the clay due to capillary action and keeps it damp. Practically no pores or capillaries exist in sand and hence water cannot rise in sand. So sand is dryer than clay.

-Answered by Shruti Srivastva On 26 September 2020:05:50:13 PM


Question 130. Asked on :26 September 2020:05:47:17 PM

How does the cotton wick in an oil-filled lamp keeping on buuring?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The narrow spaces between the threads of the wick serves as cappilary tubes through which oil keeps on rising due to capillary action.

-Answered by Shruti Srivastva On 26 September 2020:05:48:19 PM


Question 131. Asked on :26 September 2020:05:45:03 PM

How does the cotton wick in an oil-filled lamp keep on burning?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva

The narrow spaces between the threads of the wick serve as capillary tubes through which oil keeps on rising due to capillary action.

-Answered by Shruti Srivastva On 26 September 2020:05:45:53 PM


Question 132. Asked on :26 September 2020:05:42:41 PM

How does the plouging of feild help in preservation of moisture in the soil? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
THis is done to break the tiny capillaries through which water can rise nad finally evaporate. The plouging of field helps the soil to retain the moisture. 

-Answered by Shruti Srivastva On 26 September 2020:05:43:51 PM


Question 133. Asked on :26 September 2020:05:40:47 PM

What does make water proof raincoat water proof? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The angle of contact between water and the material of the raincoat. So the rainy water does not wet the raincoat.

-Answered by Shruti Srivastva On 26 September 2020:05:41:27 PM


Question 134. Asked on :26 September 2020:05:38:17 PM

Teflon is coated on the surface of non-sticking pans. Why?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
When the surface of a pan is caoted withteflon, the angle of contact between the pan and the oil used for the frying purpose become obtuse. Thus the frying pan becomes non-sticking.

-Answered by Shruti Srivastva On 26 September 2020:05:39:15 PM


Question 135. Asked on :26 September 2020:05:36:11 PM

What is the importance of water proofing agents? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
They are used to increase the angle o contact between the fabric and water to prevent the water from penertaing the cloth. 

-Answered by Shruti Srivastva On 26 September 2020:05:37:01 PM


Question 136. Asked on :26 September 2020:05:34:10 PM

What is the imporatnce of wetting agents used by dyers? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
They are added to decrease the angle of contact between the fabric and the dyer so that the dye may pentrate well. 

-Answered by Shruti Srivastva On 26 September 2020:05:35:10 PM


Question 137. Asked on :26 September 2020:05:29:58 PM

Two soap bubbles of unequal sozes are blown at the ends of a capillary tube. Which one will grow at the expends of the others and what does it show? 

-Added by Rohit Rajput Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The bigger one will grow at the expense of smaller one. This is because excess pressure is inversely proportional to radius and air flows from higher pressure two low pressure. 

-Answered by Shruti Srivastva On 26 September 2020:05:32:31 PM


Question 138. Asked on :25 September 2020:06:25:50 PM

Why excess pressure in a soap bubble is twice the excess pressure of a liquid drop of the same radius? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
A soap bubble has two ree surfaces, one internal and another external; whereas liquid drop has only ones outer free surface. 

-Answered by Shruti Srivastva On 25 September 2020:06:27:04 PM


Question 139. Asked on :25 September 2020:06:23:52 PM

The paints and lubricating oils have low surface tension. Why?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The paints and lubricating oils having low surface tension can spread over a large surface area. 

-Answered by Shruti Srivastva On 25 September 2020:06:24:52 PM


Question 140. Asked on :25 September 2020:06:21:35 PM

The addition of flux to tin makes soldering easy. Why?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The addition of flux reduces surface tension of the molten tin. This helps it spread easily over the area of soldening. 

-Answered by Shruti Srivastva On 25 September 2020:06:22:36 PM


Question 141. Asked on :25 September 2020:06:18:07 PM

A tiny liquid drop is spherical but a larger drop has oval shape. Why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
In the caseof a tiny drop, the force of surface tension is large compared to its weight, so the drop has spherical shape. A large drop has oval shape because the force o gravity exceeds the force of surface tension. 

-Answered by Shruti Srivastva On 25 September 2020:06:19:20 PM


Question 142. Asked on :25 September 2020:06:15:11 PM

Glass marbles are made by heatig the end of a glass rod until drops of molten glass all. Explain.

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
When drops of molten glass fall freely, they are is state of weightlesness. As only the force of surace tension acts on them, so they acquire spherical shape which on solidififcation become glass marbles. 

-Answered by Shruti Srivastva On 25 September 2020:06:16:23 PM


Question 143. Asked on :25 September 2020:06:14:05 PM

A oil drop on a hot cup of soup spreads over when the temperature of the soup alls. Why?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

nisha sheikh
The surface tension of oil is more than that of hor soup. Due to it, an oil drop does not spread over the hot soup. When the temperature of the soup falls, the surface tension of oil becomes less than that of soup. Due to it, the oil drop starts spreading on the soup.

-Answered by nisha sheikh On 21 October 2020:06:53:13 PM


Question 144. Asked on :25 September 2020:06:11:09 PM

How does soap help us to remove dirt better in washing clothes?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Wit the addition of soap, the surface tension of water decreaces. The decreaces in surace tension results in greater wetting and hence washing powder.  

-Answered by Shruti Srivastva On 25 September 2020:06:12:20 PM


Question 145. Asked on :25 September 2020:06:06:57 PM

The clothes are better cleaned with hot water than with cold watyer. Why?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Surface tension decreaces with the increase of temperature. Lesser the surface tension, more is the wetting power of water. 

-Answered by Shruti Srivastva On 25 September 2020:06:09:48 PM


Question 146. Asked on :25 September 2020:05:59:18 PM

Why it becomes easier to spray the surace tension of water in which some soap is dissolved?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva

 When soaps is dissolved in water, the surace tension of water decreaces and so less energy is neede for spraying the wateri.e., spraying of water in which soap is dissolved becomes is easier. 

-Answered by Shruti Srivastva On 25 September 2020:06:03:17 PM


Question 147. Asked on :25 September 2020:05:56:06 PM

A needle floats on the surface of pure water but goes down when detergent is added to water. Why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Due to addition of detergent, the surface tension and hence the reaction of surface tension decreaces. Hneca the needle sinks due to smaller upward reaction. 

-Answered by Shruti Srivastva On 25 September 2020:05:57:17 PM


Question 148. Asked on :25 September 2020:05:53:24 PM

Why do the hair of a shaving brush cling together when taking out of water? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
When the brush is taken out of water, thin water film is formed at the tips of the hair. It contracts due to surface tension and so the hair cling together. 

-Answered by Shruti Srivastva On 25 September 2020:05:54:30 PM


Question 149. Asked on :25 September 2020:05:49:58 PM

Why does a stream of water from a fascet become narrow as it falls?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
This is due to surface tension. The molecule of water come close to each other due to surface tension and surface area tends to be minimum making the stream narrow. 

-Answered by Shruti Srivastva On 25 September 2020:05:50:53 PM


Question 150. Asked on :25 September 2020:05:48:27 PM

Why hot soup tastes better than cold soup? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Hot soups has compartevily less surface tension than cold soup.

-Answered by Shruti Srivastva On 25 September 2020:05:49:13 PM


Question 151. Asked on :25 September 2020:05:46:31 PM

Antiseptics have low surface tension. Why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Low surface tension helps the antiseptic to spread over large area over the wounds.

-Answered by Shruti Srivastva On 25 September 2020:05:47:36 PM


Question 152. Asked on :25 September 2020:05:42:23 PM

Why ends o a glass tube become rounded on heating? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
When glass is heated, it melts to a liquid. The surface of this liqid tends to have a minimum area. Now , for a given volume, the area of the surface of a sphere is minimum. This is why the ends o a glass tube become rounded heating. 

-Answered by Shruti Srivastva On 25 September 2020:05:43:16 PM


Question 153. Asked on :25 September 2020:05:39:36 PM

Small insects can move about on the surface of water. Why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Due to surface tension, the free surface of water behaves like strecthed elastic membrane which is able to support the small weight of insects and they can move on the surface of water. 

-Answered by Shruti Srivastva On 25 September 2020:05:40:48 PM


Question 154. Asked on :25 September 2020:05:36:45 PM

One can from a fairly large vertical film a soap solution but not of pure water. Why?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
This is because the surface tension o soap solution ismuch smaller than that of pure water. When we try to make a vertical film of pure water, it breaks due to the high surace tension of water.  

-Answered by Shruti Srivastva On 25 September 2020:05:37:48 PM


Question 155. Asked on :25 September 2020:05:35:57 PM

 Why shape does a liquid take when it weighs nothing? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Rohit Rajput
When a liquid weighs nothing, surface tension is the only force acting on it. Due to surface tension, the liquid surface tends to occupy minimum surface area. For a given volume, the surface area of a sphere is minimum, so the liquid assumes spherical shape.

-Answered by Rohit Rajput On 26 September 2020:07:21:43 PM


Question 156. Asked on :25 September 2020:05:35:18 PM

How dental plate clinges to the roof of the mouth? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Anjali Kumari
Dental plate clings to the roof of the mouth because of the presence of adhesive force between saliva and dental plate. 

-Answered by Anjali Kumari On 11 October 2020:02:09:13 PM


Question 157. Asked on :25 September 2020:05:33:24 PM

Why does mercury collect itsel into drops when placed on a clean glass plate? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The adhensive force between mercury and glass molecules is less than the cohensive force between mercury molecule. 

-Answered by Shruti Srivastva On 25 September 2020:05:34:19 PM


Question 158. Asked on :25 September 2020:05:29:55 PM

Why does the free surface of a liquid behave like an elastic steched membrane? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The liquid molecules on the surface experince a downward force. So they have greater potential energy. In order to minimum energy, the ree surface tends to contact to minimum area and hence behaves like an elastic steched membrane. 

-Answered by Shruti Srivastva On 25 September 2020:05:31:05 PM


Question 159. Asked on :25 September 2020:05:26:10 PM

Why is it not possible to seprate two piece of paper joined by glue or gum? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The adhesive force between the molecules of glue and paper is much more than the cohensive force between the glue molecules. As a result, the two papers stick together with a large force and cannot be seprated. 

-Answered by Shruti Srivastva On 25 September 2020:05:27:10 PM


Question 160. Asked on :25 September 2020:05:24:01 PM

Mercury doesn't cling to glass. Why?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The force of adhension between mercury and glass is smaller than the force of cohension between the mercury molecules.

-Answered by Shruti Srivastva On 25 September 2020:05:24:37 PM


Question 161. Asked on :25 September 2020:05:21:00 PM

Why a glass rod caoted with wax does not become wet when dipped in water? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The reason is that force of adhension between water and wax molecules is smaller than force of cohension between water molecule.

-Answered by Shruti Srivastva On 25 September 2020:05:22:14 PM


Question 162. Asked on :24 September 2020:06:29:27 PM

Why are the cars and aeroplane gives streamline shape? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
To minimize the backward drag of atmosphere. 

-Answered by Shruti Srivastva On 24 September 2020:06:30:29 PM


Question 163. Asked on :24 September 2020:06:27:06 PM

Why bullets are given cylendrical shape? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The magnus effect is absent if the spinning cylinder is koving linearly in the direction parallel to spin axis. 

-Answered by Shruti Srivastva On 24 September 2020:06:28:18 PM


Question 164. Asked on :24 September 2020:06:23:31 PM

 An aeroplane runs for some distance on the runway before taking off. Why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Generally, air does not strike an aeroplane with a large velocity. To get lift, the aeroplane ruins for some distance on the runway before taking off.

-Answered by Shruti Srivastva On 24 September 2020:06:25:07 PM


Question 165. Asked on :24 September 2020:06:19:37 PM

When air is blown between two balls suspended close to each other, they are attached towards each other. Why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
When air is blown between the two balls, the velocity is increased and hence pressure is decreased . On the outer sides of the balls, the pressure is high and hence the two balls get attached. 

-Answered by Shruti Srivastva On 24 September 2020:06:21:21 PM


Question 166. Asked on :24 September 2020:06:15:51 PM

Poofes of the huts are blown up during stormy days. Why?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The velocity of the wind in high above the roof. So the pressure is low in accordance with Bernouilli's principle. But the pressure below the roof is the atmosphere pressure which is hogh. So the roof is blown up. 

-Answered by Shruti Srivastva On 24 September 2020:06:17:11 PM


Question 167. Asked on :24 September 2020:06:10:16 PM

Why still water runs deep?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
In case of a deep water, the cross-sectional area, through which it flows, is quite large. Hence according to equation of continuity, its velocity is small and therefore it appears to be still. 

-Answered by Shruti Srivastva On 24 September 2020:06:10:52 PM


Question 168. Asked on :24 September 2020:06:08:02 PM

What happens to the external energy maintaining the flow of a liquid when the flow becomes turbulent? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The turbulent flow of a liquid, most of the external energy maintaining the flow is used in setting up the eddies in the liquid.

-Answered by Shruti Srivastva On 24 September 2020:06:09:11 PM


Question 169. Asked on :24 September 2020:06:04:51 PM

What happens when the velocity of a liquid becomes greater than its critical velocity? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The flow of liquid changes from streamline to turbulent. 

-Answered by Shruti Srivastva On 24 September 2020:06:07:01 PM


Question 170. Asked on :24 September 2020:06:02:42 PM

Why two stremline cannot cross each other ?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The two streamlines cross each other, there will be two directions of flow at the point o intersection which is possible.

-Answered by Shruti Srivastva On 24 September 2020:06:03:32 PM


Question 171. Asked on :24 September 2020:06:01:51 PM

The sides of a horizontal pipe carrying dirty water get dirty. Why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Rohit Rajput

 While flowing through the horizontal pipe, the velocity of dirty water is maximum along the axis of the pipe and minimum near the walls of the pipe. ... Due to this, the dirt particles move outwards and get struck on the walls of the pipe. This makes the pipe dirty.

-Answered by Rohit Rajput On 26 September 2020:07:16:36 PM


Question 172. Asked on :24 September 2020:06:00:26 PM

 Fog particles have very small sizes. So their terminal velocity through air is very small. They appear suspended in the atmosphere. 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Rohit Rajput
Fog particles are very tiny spheres. Since the terminal velocity through air of fog paticles is very small so the fog particles appears suspended in the atmosphere.

-Answered by Rohit Rajput On 26 September 2020:07:19:54 PM


Question 173. Asked on :24 September 2020:05:57:42 PM

Explain why parachute is invariably used, while jumping from an aeroplane? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
A parachute experience a large viscous force due its huge structure. Hence, it descends through the air with a very small velocity and the parachute desn't get hurt. 

-Answered by Shruti Srivastva On 24 September 2020:05:58:48 PM


Question 174. Asked on :24 September 2020:05:55:01 PM

Why dust generally settles down in a closed room? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Dust particle are speres of small radii. After accuring the terminal velocity they start falling through air with uniform speed. 

-Answered by Shruti Srivastva On 24 September 2020:05:55:48 PM


Question 175. Asked on :24 September 2020:05:52:43 PM

When rain drop falling under gravity do mot grain very high velocity? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Rohit Rajput

 Explanation:When a rain drop falls under gravity throght a viscous medium (say air) a viscous drag acts on it in a direction opposite to that of motion. ... At this stage, there is no net force to ac celerate rain drop. Hence the rain drop starts moving with uniform velocity .

-Answered by Rohit Rajput On 26 September 2020:07:17:38 PM


Question 176. Asked on :24 September 2020:05:40:33 PM

Why does an object rntering the earth's atnosphere at high velocity catch fire? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva

 When an object enters the earth atmosphere at high velocity, its motion is strongly opposed by the viscous drag of air. 

-Answered by Shruti Srivastva On 24 September 2020:05:50:30 PM


Question 177. Asked on :24 September 2020:05:34:38 PM

Why should the lubricant oil be of high viscosity? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Lubricant oil is used to reduce the dry friction between various machine parts. Due to high viscosity, lubricant oils sticks to the machine parts and cannot be squeezed out during the working of the machine. 

-Answered by Shruti Srivastva On 24 September 2020:05:36:09 PM


Question 178. Asked on :24 September 2020:05:32:35 PM

Why machine parts are jammed in the winter? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva

In winter the coefficient of viscosity of the lubricating ols gets increased due to fall in temperature. 

-Answered by Shruti Srivastva On 24 September 2020:05:33:35 PM


Question 179. Asked on :24 September 2020:05:30:04 PM

Why oils of different viscosity are used in different season? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Due to the rise of temperature in summer, the viscosity of oil decreaces. Hence more viscous oils are used in summer than winter. 

-Answered by Shruti Srivastva On 24 September 2020:05:31:09 PM


Question 180. Asked on :24 September 2020:05:26:45 PM

Hotter liquids move faster than cooler ones. why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva

 The viscosity or the internal force of friction of a liquid decreaces with the increase in temperature. Hence hotter liquids move fastter than colder ones.

-Answered by Shruti Srivastva On 24 September 2020:05:27:34 PM


Question 181. Asked on :24 September 2020:05:24:54 PM

What is the efect of temperature on the viscocity and liquid and gases? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The viscocity of liquids decreaces with rise in temperature while that of gases increace with an increase in temperature. 

-Answered by Shruti Srivastva On 24 September 2020:05:25:46 PM


Question 182. Asked on :24 September 2020:05:20:26 PM

What is the reason that a constant driving force is always required for the maintainance of the flow of oil through the pipe lines in the oil refineries? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Due to viscous force between the layers of oil, the motion o liquids gets retaerded after a certain distnace. Hence a constant driving force is required for maintaining the flow of oil through the pipe line. 

-Answered by Shruti Srivastva On 24 September 2020:05:22:25 PM


Question 183. Asked on :24 September 2020:05:18:12 PM

 Stirred liquid comes to rest after some time. Why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Different layers of a stirred liquid distroy the relative motion among themselves due to internal viscous force.

-Answered by Shruti Srivastva On 24 September 2020:05:19:07 PM


Question 184. Asked on :23 September 2020:05:54:26 PM

A soft plastic bag weights the same when empty as when filled with air at atmospheric pressure. Why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The weight of air displced by the bag is same as the weight of air inside it. The increse in weight due to the filled air gets cancelled by the upthrust of air. So weight remains same when air is filled in the bag. 

-Answered by Shruti Srivastva On 23 September 2020:05:55:46 PM


Question 185. Asked on :23 September 2020:05:27:43 PM

Why a sinking ship often turns over as it becomes immersed in water? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
When the ship is floating, the metra-centre of the ship is above the centre of gravity. While sinking, the ship takes in water. As a result, the centre of gravity is raised above the metra-centre. The ship turns over due to the couple formed by the weight and the buoyant orce. 

-Answered by Shruti Srivastva On 23 September 2020:05:29:00 PM


Question 186. Asked on :23 September 2020:05:24:43 PM

A wooden cylinder floats in a vessel with its axis vertical. How will the level of water in the vesel change if the cylinder floats with its axis horizontal? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The level of water will not chage because in both cases, the cylinder displaced equal volume of water. 

-Answered by Shruti Srivastva On 23 September 2020:05:26:33 PM


Question 187. Asked on :23 September 2020:05:21:30 PM

Why is it easier to swim in sea water then in river water? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The sea water has many salts dissolved into it. So, the density of sea water is greater than that of river water. Consequently, the sea water exerts greater upthrust on the swimmer than the river water. 

-Answered by Shruti Srivastva On 23 September 2020:05:22:51 PM


Question 188. Asked on :22 September 2020:06:00:20 PM

A piece of cork is floating in water contained a beaker. What is the apparent weight of the cork piece? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The weight of the cork piece acting vertically downwards is balanced by the upthrust due to water. So the apparent weight of the floating cork piece is zero. 

-Answered by Shruti Srivastva On 22 September 2020:06:01:55 PM


Question 189. Asked on :22 September 2020:05:59:00 PM

Does the Archimedes principle hold in a vessel in free fall? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva

 no.

-Answered by Shruti Srivastva On 22 September 2020:06:00:07 PM


Question 190. Asked on :22 September 2020:05:57:13 PM

An ice cube floats in a glss of water illed to the brim. What happens when the ice melts?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva

The water level remains uncharged. 

-Answered by Shruti Srivastva On 22 September 2020:05:58:35 PM


Question 191. Asked on :22 September 2020:05:51:57 PM

A man is sitting in a boat, which is floating in a pond. If the man drinks some water from the pond, will the level of water in the pond fall? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva

 Levels remain same. 

-Answered by Shruti Srivastva On 22 September 2020:05:56:53 PM


Question 192. Asked on :22 September 2020:05:49:07 PM

A piece of iron sinks in water, but a ship made of iron floats in water. Why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The weight of water displaced by iron piece is less than its own weight, so it sinks. On the other hand, tha ship displaces water more than its own weight, so it floats. 

-Answered by Shruti Srivastva On 22 September 2020:05:50:20 PM


Answer:

Shruti Srivastva
Since there is no water under the block to exert an upward orce on it, thereore, there is no buoyant force. 

-Answered by Shruti Srivastva On 22 September 2020:05:47:59 PM


Question 194. Asked on :22 September 2020:05:41:44 PM

A liquid cannot withstand a shear stress. How does this imply that the surface of a liquid at rest must be level, i.e., normal to the gravitational force? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
If the free surface of the liquid is not perpendicular to the gravitational force, then there will be a componenet of force along the surface. The liquid will not be at rest in that case.

-Answered by Shruti Srivastva On 22 September 2020:05:44:09 PM


Question 195. Asked on :22 September 2020:05:39:46 PM

Why does a siphon fail to work in vaccum? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
As siphon works on account of atmospheric pressure, hence it fails to work in vaccum. 

-Answered by Shruti Srivastva On 22 September 2020:05:40:34 PM


Question 196. Asked on :22 September 2020:05:38:37 PM

Why an air bubble in water rises form bottom to top and grow in size? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Rohit Rajput
As air bubble rises from bottom to the top of a water tank, the size of the bubble increases. It happens, because. the pressure exerted by water on the bubble decreases as the height of the water column above it decrease. the density of water increases as we move downwads.

-Answered by Rohit Rajput On 26 September 2020:07:18:29 PM


Question 197. Asked on :22 September 2020:05:35:27 PM

The dams of water reservoir are made thick near the bottom. Why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Pressure exerted by a liquid column of height. As the value of h is greatest near the bottom, so pressure exerted by water is greatest near the bottom. So dams are made thick near the bottom. 

-Answered by Shruti Srivastva On 22 September 2020:05:36:57 PM


Question 198. Asked on :22 September 2020:05:33:06 PM

How can we check whether the barometric tube contains air or not? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
If on raising or lowering the barometric tube in a trough of mercury, the height of mercury column changes, than air is present in the barometric tube. 

-Answered by Shruti Srivastva On 22 September 2020:05:34:03 PM


Question 199. Asked on :22 September 2020:05:29:53 PM

Why is raeding of a mercury barometer always less than actual pressure? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Due to property of surface tension, mercury in the tube gets depressed. Consequqntly, the observed height of mercury in the barometer tube is less than its actual height. Thus, the reading of mercury barometer is always less than the actula pressure. 

-Answered by Shruti Srivastva On 22 September 2020:05:30:46 PM


Question 200. Asked on :22 September 2020:05:28:14 PM

Why is mercury is used in barometer?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
(i) It does not stick on the wall.

(ii) Its vapour pressure quite small. 

-Answered by Shruti Srivastva On 22 September 2020:05:28:58 PM


Question 201. Asked on :22 September 2020:05:25:23 PM

Why water is not used in barometer?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva

(i) It sticks to the walls of the barometer tube.

(ii) It has low density, A barometer with water will require a tube legth of about 11m which is unmanageable. 

-Answered by Shruti Srivastva On 22 September 2020:05:26:09 PM


Question 202. Asked on :22 September 2020:05:23:22 PM

If a drop of water vapour is introduced in a mercury barometer, how will the barometric height change? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Due to pressure exerted by water vapour, the barometric height decrases. 

-Answered by Shruti Srivastva On 22 September 2020:05:24:37 PM


Question 203. Asked on :22 September 2020:05:20:45 PM

Why are straw used to suck soft drink?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
When we suck through the straw, the pressure inside the straw becomes less than the atmospheric pressure. Due to the pressure differences, the soft drink rises in the straw and we are able to takle the soft drink. 

-Answered by Shruti Srivastva On 22 September 2020:05:21:34 PM


Question 204. Asked on :22 September 2020:05:18:12 PM

Why is it dificult to stop bleeding rom a cut in a human body at high altitudes? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The atmospheric pressure is low at high altitudes. Due to greater pressure difference in blood pressure and the atmospheric pressure, it is diicult to stop bleeding from a cut in a body. 

-Answered by Shruti Srivastva On 22 September 2020:05:19:17 PM


Question 205. Asked on :22 September 2020:05:14:42 PM

Why the passengers are advised to remove the ink from their pens while going up in an aeroplane? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
We know that the atmospheric pressure decreaces with hsight. Since ink inside the pen is filled at the atmospheric pressure exsisting n surace of the earth, it tends to come out to equalise the pressure. This can spoil the clothes of the passengers, so they are advised to rmove the ink from the pen. 

-Answered by Shruti Srivastva On 22 September 2020:05:15:44 PM


Question 206. Asked on :21 September 2020:06:22:44 PM

Why the ood is cooked faster in the pressure cooker? Why it becomes difficult to cook food at the mountains? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The pressure inside the pressure cooker is very high. The raises the boiling point of water and the temperature inside the cooker is higher than 100ºC which results in faster cooking the food. 

-Answered by Shruti Srivastva On 21 September 2020:06:24:02 PM


Question 207. Asked on :21 September 2020:06:19:48 PM

Why the boiling point of a liquid varues with pressure? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
At the boiling point, vapour pressure of the liquid is equal to the atmosheric pressure on the surface of the liquid increaces the liquid boils at higher temperature to generate greater vapour pressure. 

-Answered by Shruti Srivastva On 21 September 2020:06:20:53 PM


Question 208. Asked on :21 September 2020:06:16:23 PM

How does the boling point of liquid vary with pressure? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The boling point o a liquid increases with the pressure, or example, if the pressure is more thanthe atmospheric pressure, water bolis at a temperature higher than 100ºC.

-Answered by Shruti Srivastva On 21 September 2020:06:17:48 PM


Question 209. Asked on :21 September 2020:06:08:43 PM

What is the force on a man due to atmospheric pressure? Why on does not feel it? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Atmospheric pressure on the eaath is about 1 kg f per square centimetre. The surface area of the body of average man is about 2m2 and hence, a total force equal to about 2 × 105 N, acts on the body of a man due to atmospheric pressure =. But one does not eel this enormous orce because his blood exert a pressured slightly greater than the atmospheric pressure. 

-Answered by Shruti Srivastva On 21 September 2020:06:11:30 PM


Question 210. Asked on :21 September 2020:05:59:11 PM

Why is a slight blow on a cork of a bottle filled with a liquid suicient to break the bottle? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The blow on the cork exerts a pressure ( = f /a) on the liquid. Acccording to the pascal's law, this pressure is transmitted to the entire bottle through the liquid. Since the surace are (A) of the bottle is large, the large force ( = fA/u) so developed is sufficient to break the bottle. 

-Answered by Shruti Srivastva On 21 September 2020:06:04:03 PM


Question 211. Asked on :21 September 2020:05:56:47 PM

Why two holes are made to empty an oil tin?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
When two holes are made in the tin, air keeps on entering the tim through the other hole and maintains pressure inside. 

-Answered by Shruti Srivastva On 21 September 2020:05:58:00 PM


Question 212. Asked on :21 September 2020:05:53:39 PM

Water does not come out of a dropper unless its rubber bulb is pressed hard. Why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Water is heild inside the dropper against the atmospheric pressure. When the rubber bulb is pressed, pressure on water becomes greter than the atmospheric pressure and so water comes out. 

-Answered by Shruti Srivastva On 21 September 2020:05:54:55 PM


Question 213. Asked on :21 September 2020:05:50:57 PM

It is difficult for a man to walk on sand. Why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
This is because sand yeild under the weight of the man. This difficulty can be overcome by placing wooden plack on the sand. 

-Answered by Shruti Srivastva On 21 September 2020:05:52:16 PM


Question 214. Asked on :21 September 2020:05:47:37 PM

It is painful to walk barefooted on the groung covered with the edged pebbles. Why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
When walking, when entire weight of our body gets supported on the sharp edge of any pebble, it will exert a large pressue on our feet due to reaction. This causes considerable pain on our feet. 

-Answered by Shruti Srivastva On 21 September 2020:05:48:54 PM


Question 215. Asked on :21 September 2020:05:43:49 PM

Railway tracks are laid on the large sized wooden sleepers. Why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
The spread force due to the wieght of the train on a large area and hence reduced the pressure considerably. This, In turn, prevents yeilding of the ground under the weight of the train. 

-Answered by Shruti Srivastva On 21 September 2020:05:44:55 PM


Question 216. Asked on :21 September 2020:05:41:14 PM

Whay are the bags and suitcases provided with broad handles?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Broad handles have large area. So the force per unit area or the pressure exerted on the hand will be small while carrying the bag or the suitcase.

-Answered by Shruti Srivastva On 21 September 2020:05:42:22 PM


Question 217. Asked on :21 September 2020:05:36:06 PM

We can cut an apple easily with a sharp knife as compared to withe a blunt knife. Why?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Fluids

Answer:

Shruti Srivastva
Because the area of sharp knife is lesser than a blunt knife.

-Answered by Shruti Srivastva On 21 September 2020:05:40:40 PM


Question 218. Asked on :21 September 2020:05:30:48 PM

If S is the stress and Y is young's modulus of the material of a wire, what is the energy stored in the wire pere unit volume in terms of S and Y? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva

Elastic potential energy stored per unit volume

½ stress × strain = ½ × stress × stressY 

 = S22Y. 

-Answered by Shruti Srivastva On 21 September 2020:05:33:22 PM


Answer:

Shruti Srivastva
Here F = 200N, l = 1 mm = 10-3m

Elastic potential energy stored in the wire, 

∪ = ½ Fl = ½ × 200 × 10-3 = 0.1 J. 

-Answered by Shruti Srivastva On 21 September 2020:05:28:07 PM


Question 220. Asked on :21 September 2020:05:22:11 PM

A wire fixed at the upper and strethches by length l by applying a force F. What is the work done in stretching the wire? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
Work done in stretching the wire, 

W = 12  stetching force × increase in length 

= 12  Fl. 

-Answered by Shruti Srivastva On 21 September 2020:05:23:46 PM


Question 221. Asked on :21 September 2020:05:18:46 PM

The young's modulus of a wire of length L and radius is Y. If the length is reduced to L/2 and radius r/4, what will be its young's modulus? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
Young's modulus is a material constant. It is not affected by the change in dimensions of the wire. It will remain equal to Y. 

-Answered by Shruti Srivastva On 21 September 2020:05:21:03 PM


Question 222. Asked on :21 September 2020:05:14:41 PM

 Why are electric poles given hollow structures? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
This is because of hollow shaft is stronger than a solid shaft made from the same and equal amount of material. 

-Answered by Shruti Srivastva On 21 September 2020:05:17:45 PM


Question 223. Asked on :19 September 2020:06:18:55 PM

The ratio stress remains constant for a small deformation. What happens to this ratio if deformation is made very large? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
When the deforming force exceeds the elastic limit, the strain increaces mare rapidly than stress. Henca the ratio of stress decreaces. 

-Answered by Shruti Srivastva On 21 September 2020:05:16:10 PM


Question 224. Asked on :19 September 2020:06:15:26 PM

Why is the longer side of cross-section of girder used as depth?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva


Depression, δ = WL34 bd3 

Clearly, the depression of the girder will be small when depth d is large, because δ ∝ d-3.


-Answered by Shruti Srivastva On 19 September 2020:06:16:26 PM


Question 225. Asked on :19 September 2020:06:13:18 PM

A hard wire is broken by bending it repeadetly in alternating directions. Why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
When wire is subjected to repeated alternating strains, the strength of its material decreaces and the wire breakes. 

-Answered by Shruti Srivastva On 19 September 2020:06:14:27 PM


Question 226. Asked on :19 September 2020:06:10:04 PM

Why does a wire get heated when it is bent back and forth? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
Its deformation are beyond elastic limit. The work done aginst interomic force is no longer stord tottaly in the form of potential energy. The crystalline structure of the wire gets afected and work done is converted into heat energy. 

-Answered by Shruti Srivastva On 19 September 2020:06:10:51 PM


Question 227. Asked on :19 September 2020:06:07:21 PM

Two identical springs of steel and copper are pulled by applyig equal force, then in which case more work will have to be done? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
Steel spring will be stretched to a lesses extent. Now more work will be done on the copper string. 

-Answered by Shruti Srivastva On 19 September 2020:06:08:55 PM


Question 228. Asked on :19 September 2020:06:05:24 PM

What happens to work done in stretching a wire? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
Thje work done in stretching a wire is stored in it as elstic potential energy.

-Answered by Shruti Srivastva On 19 September 2020:06:06:18 PM


Question 229. Asked on :19 September 2020:06:04:00 PM

Why are springs made of steel and not of copper? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
Because steel stretched lesser than a copper. 

-Answered by Shruti Srivastva On 19 September 2020:06:04:38 PM


Question 230. Asked on :19 September 2020:06:02:16 PM

Which is more elasctic ------ water or air?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva

 water

-Answered by Shruti Srivastva On 19 September 2020:06:03:19 PM


Question 231. Asked on :19 September 2020:06:00:05 PM

Write copper, stell, glass and rubber in the order of increasing coefficent of elsticity.

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva

rubber <  glass < copper < stell. 

-Answered by Shruti Srivastva On 19 September 2020:06:01:27 PM


Question 232. Asked on :19 September 2020:05:59:03 PM

How does young's modulus change with the rise pf temperature? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
Decrease. 

-Answered by Shruti Srivastva On 19 September 2020:05:59:55 PM


Question 233. Asked on :19 September 2020:05:57:54 PM

What does the slope of stress versus strain graph given? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
Elasticity. 

-Answered by Shruti Srivastva On 19 September 2020:05:58:48 PM


Question 234. Asked on :19 September 2020:05:56:11 PM

Which typr of elasticity is envolved in Tangential push on the upper face o a block?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
Modulus of rigidity. 

-Answered by Shruti Srivastva On 19 September 2020:05:57:34 PM


Question 235. Asked on :19 September 2020:05:55:02 PM

Which type of elasticity envolved in stretching a wire? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
Young's moduls.

-Answered by Shruti Srivastva On 19 September 2020:05:55:51 PM


Question 236. Asked on :19 September 2020:05:53:58 PM

Which type of elasticity envolved in compressing of liquid? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
Bulk modulus.

-Answered by Shruti Srivastva On 19 September 2020:05:54:44 PM


Question 237. Asked on :19 September 2020:05:51:03 PM

Which type o elsticity is involved in the Compressing of gas? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
Bulk modulus. 

-Answered by Shruti Srivastva On 19 September 2020:05:52:29 PM


Question 238. Asked on :19 September 2020:05:49:33 PM

Among solid , liquid and gas which possess the greatest bulk modulus?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva

solid 

-Answered by Shruti Srivastva On 19 September 2020:05:50:48 PM


Question 239. Asked on :19 September 2020:05:48:03 PM

Among solids liquids and gases, which can have all the three moduli of elasticity?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva

solids 

-Answered by Shruti Srivastva On 19 September 2020:05:49:25 PM


Question 240. Asked on :19 September 2020:05:44:37 PM

Stress and pressure are both forces per unit area. Then in what respect does stress differ rom pressure? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
Pressure is the external force per unit area, while stress is the internal restoring force which comes into play in a deformed body acting transversly per unit area of the body.

-Answered by Shruti Srivastva On 19 September 2020:05:45:57 PM


Question 241. Asked on :19 September 2020:05:43:33 PM

Is elastic limit a property of the material of the wire?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva

No.

-Answered by Shruti Srivastva On 19 September 2020:05:44:26 PM


Question 242. Asked on :19 September 2020:05:42:06 PM

Is it is possible to double the length of a mettalic wire by applying a force over it?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
No.

-Answered by Shruti Srivastva On 19 September 2020:05:43:16 PM


Question 243. Asked on :19 September 2020:05:39:47 PM

State the two factor on which the modulus of elasticity depends?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva

(i) Nature of the material.

(ii) Type of stress used in producing the strain.

-Answered by Shruti Srivastva On 19 September 2020:05:40:53 PM


Question 244. Asked on :19 September 2020:05:36:22 PM

A thick wire is suspended from a rigid support, but no load is attached to its free end. Is this wire under stress? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
Yes. 

-Answered by Shruti Srivastva On 19 September 2020:05:39:29 PM


Question 245. Asked on :19 September 2020:05:32:59 PM

When does a body acquire a permanent set?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
When the deforming force exceeds the elastic limit, the body acqire the peramanent set.

-Answered by Shruti Srivastva On 19 September 2020:05:33:43 PM


Question 246. Asked on :19 September 2020:05:31:01 PM

No material is perfectly elastic. why? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
All materials undergo a change in their original state, however small it may be, after the removal o deforming force. 

-Answered by Shruti Srivastva On 19 September 2020:05:31:40 PM


Question 247. Asked on :19 September 2020:05:30:02 PM

Write an example of perfectly plastic? 

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
Putty. 

-Answered by Shruti Srivastva On 19 September 2020:05:30:49 PM


Question 248. Asked on :19 September 2020:05:27:55 PM

What is a perfectly plastic body?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Answer:

Shruti Srivastva
If, on removal of deforming force, a body does not regain its original confriguation even a little, then it is said to be perfectly plastic?

-Answered by Shruti Srivastva On 19 September 2020:05:28:38 PM


Question 249. Asked on :19 September 2020:05:26:39 PM

Write an example of perfectly elastic? 

-Added by Shruti Srivastva Physics » Machenical Properties Of Solids

Answer:

Shruti Srivastva
quartz.

-Answered by Shruti Srivastva On 19 September 2020:05:27:33 PM


Question 250. Asked on :19 September 2020:05:23:38 PM

What is a perfectly plastic body? 

-Added by Shruti Srivastva Physics » Machenical Properties Of Solids

Answer:

Shruti Srivastva
If, on removal of deforming force, a body completely regains its original configuration, then it is said to be perectly elastic.

-Answered by Shruti Srivastva On 19 September 2020:05:24:24 PM


Question 251. Asked on :19 September 2020:05:21:08 PM

Crystalline solid are called true solid why?

-Added by Shruti Srivastva Physics » Machenical Properties Of Solids

Answer:

Shruti Srivastva
This is because crystalline solids have well defined, regularly repeated three dimensional arrangment of atoms or molecules. 

-Answered by Shruti Srivastva On 19 September 2020:05:22:04 PM


Question 252. Asked on :19 September 2020:05:18:31 PM

Our knowledge about crystalline solids is better than amorphous solids. Why?

-Added by Shruti Srivastva Physics » Machenical Properties Of Solids

Answer:

Shruti Srivastva
As crystalline solids possess long range and regular arrangement of atoms, hence their behavior can be easily understood. 

-Answered by Shruti Srivastva On 19 September 2020:05:19:43 PM


Question 253. Asked on :19 September 2020:05:15:28 PM

Amorphous solids are not true solids. Why and what are they called then?

-Added by Shruti Srivastva Physics » Machenical Properties Of Solids

Answer:

Shruti Srivastva
The amorphous solids are rigid due to their high viscocity. That is why, we say amorphous solids are super-cooled liquids of high viscocity. 

-Answered by Shruti Srivastva On 19 September 2020:05:16:43 PM


Question 254. Asked on :18 September 2020:06:24:40 PM

Why do crystalline solid have well deined geometrical external shape?

-Added by Shruti Srivastva Physics » Machenical Properties Of Solids

Answer:

Shruti Srivastva
This is because of atom and molecules are arranged in a definite geometrical repeating manner throughout the body of the crystal. 

-Answered by Shruti Srivastva On 18 September 2020:06:25:35 PM


Question 255. Asked on :18 September 2020:06:22:03 PM

In what respect, the behaviour of glassy solid is similar to that of the liquids? 

-Added by Shruti Srivastva Physics » Machenical Properties Of Solids

Answer:

Shruti Srivastva
In case of glassy solids, the orderly arrangment of atoms is limited to a very short range and in this respact they are similar to liquids.

-Answered by Shruti Srivastva On 18 September 2020:06:23:04 PM


Question 256. Asked on :18 September 2020:06:17:25 PM

Amorphous solids do not melt at a sharp temparature, rather these have softening range. Explain this observation. 

-Added by Shruti Srivastva Physics » Machenical Properties Of Solids

Answer:

Shruti Srivastva
All bons in an amorphous solid are not equally strong. When the solid is heated, weaker bonds get reputed at lower temperature and the stronger ones at higher temperature. So the sold irst softens and then inally melts. 

-Answered by Shruti Srivastva On 18 September 2020:06:19:36 PM


Question 257. Asked on :18 September 2020:06:13:51 PM

What is the importatnt structural differences between crystalline and glassy solids? 

-Added by Shruti Srivastva Physics » Machenical Properties Of Solids

Answer:

Shruti Srivastva

In a crystalline solids the atoms or molecules are arrnged in a definite and long range order, but in glassy solids there exsists no such long range order in the arrangement of atoms or molecule.

-Answered by Shruti Srivastva On 18 September 2020:06:15:14 PM


Question 258. Asked on :18 September 2020:06:11:23 PM

What do you mean by long range order in a crystalline structure? 

-Added by Shruti Srivastva Physics » Machenical Properties Of Solids

Answer:

Shruti Srivastva

 That similar pattern of atom or molecules repeat over a large distance in a crystal. 

-Answered by Shruti Srivastva On 18 September 2020:06:12:28 PM


Question 259. Asked on :18 September 2020:06:08:43 PM

State the factors due to the three states of matter differ from each other? 

-Added by Shruti Srivastva Physics » Machenical Properties Of Solids

Answer:

Shruti Srivastva

 (i) Different 

magnitudes of intermolecular force.

(ii) Degree of random thermal motion of the atoms and the moleccules of a substance depending on temperature. 

-Answered by Shruti Srivastva On 18 September 2020:06:10:03 PM


Question 260. Asked on :18 September 2020:06:05:27 PM

Are the intermolecular forces involved in the formation of liquids and solids different in nature? If yes, how?

-Added by Shruti Srivastva Physics » Machenical Properties Of Solids

Answer:

Shruti Srivastva
Yes. The intermolecular forces involved in the formation of liquids and solids different in nature while in the ormation of solids, the repulsive intermolecular forces are more important. 

-Answered by Shruti Srivastva On 18 September 2020:06:06:31 PM


Question 261. Asked on :18 September 2020:06:03:35 PM

What is the origin of intermolecular force ? 

-Added by Shruti Srivastva Physics » Machenical Properties Of Solids

Answer:

Shruti Srivastva
Intermolecular force arises due to the electrostatic interaction between the opposite charged ends of molecular dipoles. 

-Answered by Shruti Srivastva On 18 September 2020:06:04:19 PM


Question 262. Asked on :18 September 2020:06:01:23 PM

What is the origin of intermolecular force?

-Added by Shruti Srivastva Physics » Machenical Properties Of Solids

Answer:

Shruti Srivastva
Intermolic force arises due to the electrostatic interaction between the nuclie of two atoms, their electron clouds and between the nucleus of an atom and the electron cloud of the other atom. 

-Answered by Shruti Srivastva On 18 September 2020:06:01:57 PM


Question 263. Asked on :18 September 2020:05:58:58 PM

 What is the nature of intermolecular forces?

-Added by Shruti Srivastva Physics » Machenical Properties Of Solids

Answer:

Shruti Srivastva

Generally the intermolecular forces are attractive, but they are repulsive for intermolecular seprations less than 10-10m.

-Answered by Shruti Srivastva On 18 September 2020:06:00:05 PM


Question 264. Asked on :30 August 2020:12:31:59 AM

 The electrical fieldin terms of spherical cooriinates is defined as follows 

E=Kr

3

-Added by Raj kumar Physics » EMT


Question 265. Asked on :20 August 2020:06:08:42 PM

On getting Gopu Mama’s chappals, the music teacher tried not to look too happy. Why? 

-Added by Shruti Srivastva Physics » A Gift Of Chappals

Answer:

Anjali Kumari
On getting Gopu Mama's new chappals, he was happy but tried to look not too happy as he didn't want to show his happiness to the house members and moreover wanted to prove that his own chapplas were much better and more expensive than those he got and thus, was compromising on them.

-Answered by Anjali Kumari On 12 October 2020:07:25:49 PM


Question 266. Asked on :20 August 2020:05:58:14 PM

 What is the secret that Meena shares with Mridu in the backyard?

-Added by Shruti Srivastva Physics » A Gift Of Chappals

Answer:

nisha sheikh
 A kitten inside a torn football filled with sand was hidden behind a thick bitter-berry bush in the backyard. This was the secret that Meena shared with Mridu.

-Answered by nisha sheikh On 23 October 2020:07:00:05 PM


Question 267. Asked on :19 August 2020:05:50:45 PM

What is homogenous? 

-Added by Shruti Srivastva Physics » Is Matter Around Us Pure

Answer:

Shruti Srivastva
It has a uniform composition.

-Answered by Shruti Srivastva On 19 August 2020:05:51:18 PM


Question 268. Asked on :19 August 2020:05:47:53 PM

What is a solution?                       

-Added by Shruti Srivastva Physics » Matter In Our Surroundings

Answer:

Shruti Srivastva
A matter which has a specific properties and specific composition. Every pure element is a substance. 

-Answered by Shruti Srivastva On 19 August 2020:05:49:01 PM


Question 269. Asked on :18 August 2020:05:41:09 PM

Give the SI unit of inductive reactance?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
ohmΩ.

-Answered by Shruti Srivastva On 18 August 2020:05:43:13 PM


Question 270. Asked on :18 August 2020:05:37:19 PM

The instantaneous current and voltage of an a.c. circuit are given by 


i = 10 sin 314t A and V = 50 sin 314 t V.


What is the power dissipation in the circuit?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva

Pav = v0i02 

cos Φ= 50 X 102 

cos 0º = 250 W.

-Answered by Shruti Srivastva On 18 August 2020:05:39:28 PM


Question 271. Asked on :18 August 2020:05:33:17 PM

Give expression for the average value of the a.c. voltage V = VO sin ωt over the time interval t = 0 and t = π
ω
 .

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva

Vav = 2π
 V0  = 0.637 V0.

-Answered by Shruti Srivastva On 18 August 2020:05:35:54 PM


Question 272. Asked on :18 August 2020:05:29:44 PM

The power factor of an a.c. circuit is 0.5. What will be the phase difference between voltage and current in this circuit?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva

Power factor = cosΦ = 0.5

Phase difference,Φ = 60º.

-Answered by Shruti Srivastva On 18 August 2020:05:31:36 PM


Question 273. Asked on :18 August 2020:05:28:08 PM

How can iron loss in a transformer be reduced? 

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
It can be reduced by using a laminated core in the transformer. 

-Answered by Shruti Srivastva On 18 August 2020:05:29:00 PM


Question 274. Asked on :18 August 2020:05:26:07 PM

What is iron loss in a transformer?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
Due to the production of eddy currents in the iron core of a transformer, some electrical energy is wasted as heat. This energy loss is called iron loss. 

-Answered by Shruti Srivastva On 18 August 2020:05:26:40 PM


Question 275. Asked on :18 August 2020:05:23:33 PM

What is copper loss in a transformer?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
Due to the resistance of primary and secondary windings of a transformer, some electrical energy is wasted as heat. The energy loss is called copper loss. 

-Answered by Shruti Srivastva On 18 August 2020:05:24:15 PM


Question 276. Asked on :18 August 2020:05:22:13 PM

Can we use transformer to set up d.c. voltage?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
No. 

-Answered by Shruti Srivastva On 18 August 2020:05:23:21 PM


Question 277. Asked on :18 August 2020:05:20:56 PM

Which device will you use to set up a.c. voltage?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
Transformer.

-Answered by Shruti Srivastva On 18 August 2020:05:22:01 PM


Question 278. Asked on :18 August 2020:05:19:17 PM

Give two reasons for power loss in a transformer?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
(i) Magnetic flux leakage. 

(ii) Hysteresis loss.

-Answered by Shruti Srivastva On 18 August 2020:05:20:08 PM


Question 279. Asked on :18 August 2020:05:16:56 PM

State the principle of the transformer?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
It works on the principle of mutual induction i.e., when a charging current is passed through one coil, an induced emf is set up in the neighbouring coil.

-Answered by Shruti Srivastva On 18 August 2020:05:17:35 PM


Question 280. Asked on :18 August 2020:05:15:18 PM

How can an a.c. generator be converted into d.c. generator?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
By replacing slip rings by split ring commutator.

-Answered by Shruti Srivastva On 18 August 2020:05:16:10 PM


Question 281. Asked on :18 August 2020:05:14:26 PM

State the principles of a.c. generator?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Rohit Rajput
AC generators work on the principle of Faraday's law of electromagnetic induction which states that electromotive force -EMF or voltage – is generated in a current-carrying conductor that cuts a uniform magnetic field.

-Answered by Rohit Rajput On 26 September 2020:07:25:09 PM


Question 282. Asked on :17 August 2020:06:25:11 PM

What is direct current?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Anjali Kumari
 flow of electricity that goes in one direction only

-Answered by Anjali Kumari On 12 October 2020:07:45:14 PM


Question 283. Asked on :17 August 2020:06:24:12 PM

What is alternating current?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Anjali Kumari
a flow of electricity that changes direction regularly many times a second

-Answered by Anjali Kumari On 12 October 2020:07:46:14 PM


Question 284. Asked on :17 August 2020:06:16:10 PM

Where does the energy reside in an inductor when a current I0 is established in it?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
The energy reside in the magnetif field of the inductor coil?

-Answered by Shruti Srivastva On 17 August 2020:06:17:37 PM


Question 285. Asked on :17 August 2020:06:14:38 PM

Where does the energy reside in a charged capacitor?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
The energy resides in the electric field between the plates of a charged capacitor.

-Answered by Shruti Srivastva On 17 August 2020:06:15:11 PM


Question 286. Asked on :17 August 2020:06:12:19 PM

In pure LC circuit, what is the energy stored when peak current is I0?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva

Total energy stored= 12 LI02.

-Answered by Shruti Srivastva On 17 August 2020:06:13:31 PM


Question 287. Asked on :17 August 2020:06:11:12 PM

What are the dimensions of √LC?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
{M0L0T1}

-Answered by Shruti Srivastva On 17 August 2020:06:11:57 PM


Question 288. Asked on :17 August 2020:06:08:38 PM

What is the natural frequency of LC circuit?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva

                                   

The natural frequency of LC circuit

F= 12π√LC 

-Answered by Shruti Srivastva On 17 August 2020:06:09:35 PM


Question 289. Asked on :17 August 2020:06:07:19 PM

Is the direction of current during the discharging of capacitor same as that during the charging process?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
No.

-Answered by Shruti Srivastva On 17 August 2020:06:08:25 PM


Question 290. Asked on :17 August 2020:06:06:26 PM

What are units of product RC?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
Second.

-Answered by Shruti Srivastva On 17 August 2020:06:06:58 PM


Question 291. Asked on :17 August 2020:06:05:05 PM

What are dimensions of product RC?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
M0L0T1

-Answered by Shruti Srivastva On 17 August 2020:06:05:51 PM


Question 292. Asked on :17 August 2020:06:03:37 PM

How can we improve the Q-factor o a series resonance current?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
By decreasing R or C or by increasing L.

-Answered by Shruti Srivastva On 17 August 2020:06:04:26 PM


Question 293. Asked on :17 August 2020:06:01:51 PM

What is the function of a choke coil in a flurescent tube?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
A choke coil reduces current without wasting electrical energy in the form of heat.

-Answered by Shruti Srivastva On 17 August 2020:06:02:46 PM


Question 294. Asked on :17 August 2020:05:59:08 PM

In a serie LCR circuit, VL = VC = VR. What is the value of power factor?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
Power factor, cos Φ = 1

-Answered by Shruti Srivastva On 17 August 2020:06:00:42 PM


Question 295. Asked on :17 August 2020:05:57:21 PM

What are the factors on which the power factor?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
It depends on the value of L and R and the frequency o a.c. sourece.

-Answered by Shruti Srivastva On 17 August 2020:05:57:59 PM


Question 296. Asked on :17 August 2020:05:52:13 PM

A series LCR circuit is connected to an a.c.c source. In which of its part power dissipation occurs- L,C or R? 

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
Ressistance R. 

-Answered by Shruti Srivastva On 17 August 2020:05:54:10 PM


Question 297. Asked on :17 August 2020:05:35:06 PM

What is wattless current?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
The current in an a.c. circuit is wattless if the average power consumed in the circuit is zero.

-Answered by Shruti Srivastva On 17 August 2020:05:35:52 PM


Question 298. Asked on :17 August 2020:05:31:15 PM

What is the power factor of an LCR series circuit at resonance?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
At resonance, Z = R.

 power factor, cos Φ= RZ 

                              = RR  = 1  

-Answered by Shruti Srivastva On 17 August 2020:05:32:43 PM


Question 299. Asked on :17 August 2020:05:29:34 PM

What are the maximum and minimum values of power factor of a.c. circuit?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
Maximum = 1

Minimum = 0

-Answered by Shruti Srivastva On 17 August 2020:05:30:41 PM


Question 300. Asked on :17 August 2020:05:27:34 PM

Define power factor. 

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
The power actor is defined as the ratio of true power to the apparent power of an a.c. current.

-Answered by Shruti Srivastva On 17 August 2020:05:28:33 PM


Question 301. Asked on :17 August 2020:05:25:49 PM

What is meant by admittance of an a.c. current?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
The reciprocal of the impedance of an a.c. circuit is called its admittance. 

-Answered by Shruti Srivastva On 17 August 2020:05:26:45 PM


Question 302. Asked on :17 August 2020:05:23:31 PM

When does a series LCR-circuit have minimum impedance?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
At resotance,  when XL XC.

-Answered by Shruti Srivastva On 17 August 2020:05:24:28 PM


Question 303. Asked on :17 August 2020:05:17:39 PM

What is the capacitive reactance of a capacitor used in a circuit having d.c. emf?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
For d.c., f = 0,

 so, X= 12π f C = 

-Answered by Shruti Srivastva On 17 August 2020:05:19:19 PM


Question 304. Asked on :15 August 2020:05:46:11 PM

Give the phase difference between the appied a.c. voltage and the circuit in an LCR circuit at resonance. 

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva

zero. 

-Answered by Shruti Srivastva On 15 August 2020:05:47:37 PM


Question 305. Asked on :15 August 2020:05:42:24 PM

What is the phase differnce between the voltage across L and C in a series LCR circuit connected to an a.c. source?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
180° and π radian. 

-Answered by Shruti Srivastva On 15 August 2020:05:43:55 PM


Question 306. Asked on :15 August 2020:05:39:45 PM

What is phase relationship between current and en in an a.c. circuit containing a capacitor only?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
In a capacitor a.c. circuit leads the emf in phase by π/2 radian. 

-Answered by Shruti Srivastva On 15 August 2020:05:41:21 PM


Question 307. Asked on :15 August 2020:05:36:26 PM

What is the phase relationship between current and voltage in an inductor?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva

In an inductor, the current lage behind the voltage by a phase angle of π/2 rad.

-Answered by Shruti Srivastva On 15 August 2020:05:38:16 PM


Question 308. Asked on :15 August 2020:05:34:25 PM

What is the reactance of a capacitor of capacitance C at  hertz?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva

Xc = 12π f C .

-Answered by Shruti Srivastva On 15 August 2020:05:35:33 PM


Question 309. Asked on :15 August 2020:05:32:52 PM

Write the SI unit of 1 / ωC ?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
ohm Ω.

-Answered by Shruti Srivastva On 15 August 2020:05:33:59 PM


Question 310. Asked on :15 August 2020:05:31:11 PM

How does the inductive reactance depend on of a.c.?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
Directly.

-Answered by Shruti Srivastva On 15 August 2020:05:32:32 PM


Question 311. Asked on :15 August 2020:05:28:12 PM

How does the capacitive reactance depends on frequency of a.c.?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva

Capacitive reactance varies inversely with frequncy of a.c.

-Answered by Shruti Srivastva On 15 August 2020:05:29:17 PM


Question 312. Asked on :15 August 2020:05:27:28 PM

Write the SI unit of capacitive reactance.

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
ohm Ω.

-Answered by Shruti Srivastva On 15 August 2020:05:27:56 PM


Question 313. Asked on :15 August 2020:05:25:21 PM

Define capacitive reactance. 

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
The capacitive reactance of a capacitor is the elective resistance offered by it to the flow of current through it.

-Answered by Shruti Srivastva On 15 August 2020:05:26:04 PM


Question 314. Asked on :15 August 2020:05:24:12 PM

Write the SI unit of inductive reactance?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
ohm Ω.

-Answered by Shruti Srivastva On 15 August 2020:05:24:59 PM


Question 315. Asked on :15 August 2020:05:20:44 PM

Define inductive reactance?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
The inductive reactance of an inductor is the elective resistance offered by it to the flow of current through it. 

-Answered by Shruti Srivastva On 15 August 2020:05:21:56 PM


Question 316. Asked on :15 August 2020:05:20:02 PM

What is form factor?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva

It is the ratio of the arms value of a.c. to its average value.

-Answered by Shruti Srivastva On 15 August 2020:05:23:24 PM


Question 317. Asked on :15 August 2020:05:16:38 PM

Define the root mean square value of an alternating current.

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
It is the value of d.c. which produces the same heating effect in a given resitor as is produced by the given alternating current when passed for the same time.

-Answered by Shruti Srivastva On 15 August 2020:05:17:54 PM


Question 318. Asked on :15 August 2020:05:15:36 PM

Write the full form of RMS?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
Root Mean Square.

-Answered by Shruti Srivastva On 15 August 2020:05:16:11 PM


Question 319. Asked on :15 August 2020:05:14:34 PM

Write the full form of a.c.?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
Alternating current. 

-Answered by Shruti Srivastva On 15 August 2020:05:15:17 PM


Question 320. Asked on :15 August 2020:05:13:21 PM

Write the full form of d.c.?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva

direct current. 

-Answered by Shruti Srivastva On 15 August 2020:05:14:19 PM


Question 321. Asked on :15 August 2020:05:10:32 PM

Define the mean value of an alternating current. 

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
It is that value of d.c. which sends the same charge in a circuit in the same time as is sent by the given alternating current in its half time period.

-Answered by Shruti Srivastva On 15 August 2020:05:11:16 PM


Question 322. Asked on :15 August 2020:05:09:39 PM

What is the frequency of direct current?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
zero.

-Answered by Shruti Srivastva On 15 August 2020:05:10:21 PM


Question 323. Asked on :15 August 2020:05:06:40 PM

What is an alternating current?

-Added by Shruti Srivastva Physics » Alternating Current And Electrical Machines

Answer:

Shruti Srivastva
It is that current which changes continously in magnitude and periodically in direction. 

-Answered by Shruti Srivastva On 15 August 2020:05:08:10 PM


Question 324. Asked on :15 August 2020:05:03:54 PM

How does the mutual inductance of a pair of coils change, when number of turns in each coil is increased?

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
M increases. 

-Answered by Shruti Srivastva On 15 August 2020:05:05:23 PM


Question 325. Asked on :15 August 2020:05:02:27 PM

How does the mutual inductance o a pair os coil change when the distance between the coils is increased?

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
M decreaces.

-Answered by Shruti Srivastva On 15 August 2020:05:03:38 PM


Question 326. Asked on :15 August 2020:04:59:19 PM

Name any two useful applications of eddy currents.

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
(i) In electric furnaces to melt metals.

(ii) In electromagnetic damping in galvonometers.

-Answered by Shruti Srivastva On 15 August 2020:05:01:09 PM


Question 327. Asked on :15 August 2020:04:58:28 PM

Define mutual inductance of one henry.

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Anjali Kumari
The two coils are said to have a mutual inductance of one Henry if an emf of 1 volt is induced in one coil or say primary coil when the current flowing through the other neighbouring coil or secondary coil is changing at the rate of 1 ampere/second

-Answered by Anjali Kumari On 13 October 2020:07:21:25 PM


Question 328. Asked on :15 August 2020:04:57:12 PM

What is the unit of mutual inductance?

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
henry. 

-Answered by Shruti Srivastva On 15 August 2020:04:58:08 PM


Question 329. Asked on :15 August 2020:04:54:56 PM

Deine coeffeicent of mutual inductance for a pair of coils.

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
It is defiend as the induced emf set up in one coil when the current in the neighbouring coil changes at the unit rate. 

-Answered by Shruti Srivastva On 15 August 2020:04:55:55 PM


Question 330. Asked on :15 August 2020:04:52:38 PM

What is meant by mutual induction?

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
The phenomenon of production of induced emf in one coil due to a change of current in the neighbouring coil is called mutual induction.

-Answered by Shruti Srivastva On 15 August 2020:04:53:20 PM


Question 331. Asked on :15 August 2020:04:50:03 PM

Write two factors on which the self-inductance of coil depends.

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva

(i) Its number of turns, 

(ii) Its area of cross-section.


-Answered by Shruti Srivastva On 15 August 2020:04:51:24 PM


Question 332. Asked on :15 August 2020:04:48:41 PM

Write the SI unit of self-inductance.

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
henry (H).

-Answered by Shruti Srivastva On 15 August 2020:04:49:30 PM


Question 333. Asked on :15 August 2020:04:46:35 PM

State Lenz's law.

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
The direction of induced current is such that it opposes the cause which produces it. 

-Answered by Shruti Srivastva On 15 August 2020:04:47:14 PM


Question 334. Asked on :15 August 2020:04:44:52 PM

A glass rod of length l moves withe the velocity v perpendicular to a uniform magnetic field B. What is the induced emf in the rod?

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
Zero.

-Answered by Shruti Srivastva On 15 August 2020:04:46:21 PM


Question 335. Asked on :15 August 2020:04:41:58 PM

When the current flowing in an inductive circuit is switched off, will the induced current be in the direction of main current or in opposite direction?

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva

 When the circuit is switched off, the induced current is in the same direction as the main current.

-Answered by Shruti Srivastva On 15 August 2020:04:43:37 PM


Question 336. Asked on :15 August 2020:04:38:21 PM

How would you detect the presence of magnetic field on an unknown planet? 

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
Take a closed coil connected to a sensitive galvanometer and rotate the coil. I the galvanometer shows a deflection, a magnetic field is present on the planet, otherwise not. 

-Answered by Shruti Srivastva On 15 August 2020:04:39:54 PM


Question 337. Asked on :15 August 2020:04:35:39 PM

A coil of metal wire is held stationary in a non-uniform magnetic field. Is any emf induced in the coil?

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
The magnitude of induced emf is directly proportional to the rate of change o magnetic flux linked with the circuit.

-Answered by Shruti Srivastva On 15 August 2020:04:37:06 PM


Question 338. Asked on :15 August 2020:04:34:13 PM

State Faraday's law of electromagnetic induction.

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Anjali Kumari

 When a DC current passes through a long straight conductor a magnetising force and a static magnetic field is developed around it

-Answered by Anjali Kumari On 21 November 2020:07:01:48 PM


Question 339. Asked on :15 August 2020:04:32:57 PM

How wber is related to Maxwell?

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
1 weber = 108 maxwell

-Answered by Shruti Srivastva On 15 August 2020:04:33:50 PM


Question 340. Asked on :15 August 2020:04:27:26 PM

Define weber. 

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
One weber is the flux produced when a uniform magnetic field of one tesla acts normally over an area of 1m2.

-Answered by Shruti Srivastva On 15 August 2020:04:27:58 PM


Question 341. Asked on :15 August 2020:04:26:30 PM

Write the dimensional formula of magnetic flux.

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Anjali Kumari

Dimensional Formula of Magnetic Flux

The dimensional formula of Magnetic Flux is given by,

[M1 L2 I-1 T-2]

Where,

  • M = Mass
  • I = Current
  • L = Length
  • T = Time

-Answered by Anjali Kumari On 21 November 2020:07:04:06 PM


Question 342. Asked on :15 August 2020:04:25:36 PM

Nam the SI units of magnetic induction?

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
tesla (T). 

-Answered by Shruti Srivastva On 15 August 2020:04:26:09 PM


Question 343. Asked on :15 August 2020:04:23:54 PM

Name the SI units of magnetic flux?

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
weber (WB).

-Answered by Shruti Srivastva On 15 August 2020:04:25:06 PM


Question 344. Asked on :15 August 2020:04:22:05 PM

When is the flux linked with a closed coil held in a magnetic field zero?

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
When the plane o the coil is parallel to the magnetic field, flux linked with it is zero.

-Answered by Shruti Srivastva On 15 August 2020:04:23:06 PM


Question 345. Asked on :15 August 2020:04:19:57 PM

When is the magnetic flux crossing a given surface area held in a magnetic field maximum?

-Added by Shruti Srivastva Physics » Electromagnetic Induction

Answer:

Shruti Srivastva
The flux is maximum when the area is held perpendicular to the direction of the magnetic field.

-Answered by Shruti Srivastva On 15 August 2020:04:21:27 PM


Question 346. Asked on :13 August 2020:06:09:35 PM

What is natural magnet?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

nisha sheikh

 natural magnet is a magnet that occurs naturally in nature.

-Answered by nisha sheikh On 14 August 2020:10:13:37 AM


Question 347. Asked on :13 August 2020:06:09:14 PM

What is magnet?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

nisha sheikh

 magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, and attracts or repels other magnets.

-Answered by nisha sheikh On 14 August 2020:10:14:15 AM


Question 348. Asked on :13 August 2020:06:06:05 PM

Mention 1 characterstics properties of the material suitable for making core of a transformer.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
High intial permeability.

-Answered by Shruti Srivastva On 13 August 2020:06:07:58 PM


Question 349. Asked on :13 August 2020:06:02:44 PM

How does the magnetic permeability µ, differ for dia, para and feromagnetic materials?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
For diamagnetic, µ, <1

For paramagnetic, μ, > 1

For ferromagnetic substances, μ, >>1

-Answered by Shruti Srivastva On 13 August 2020:06:04:06 PM


Question 350. Asked on :13 August 2020:06:01:10 PM

Give example of permanent magnet.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
cobalt and steel.

-Answered by Shruti Srivastva On 13 August 2020:06:01:53 PM


Question 351. Asked on :13 August 2020:05:59:01 PM

What are permanent magnet?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
The substance which at room tempreature retain their ferromagnetism for a long time are called permanent magnet.

-Answered by Shruti Srivastva On 13 August 2020:05:59:41 PM


Question 352. Asked on :13 August 2020:05:56:10 PM

Suggest two methods to destroy the magnetism of a magnet.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
(i) By heating the magnet.

(ii) By applying magnetic field in the reverse direction. 

-Answered by Shruti Srivastva On 13 August 2020:05:57:18 PM


Question 353. Asked on :13 August 2020:05:54:03 PM

Name two magnetic material commonly used for making permanent magnets.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
Cobalt steel and Alnico.

-Answered by Shruti Srivastva On 13 August 2020:05:55:10 PM


Question 354. Asked on :13 August 2020:05:52:12 PM

Name two alloys commonly used for making cores of transormers.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
Mu-metal and Pu-metal.

-Answered by Shruti Srivastva On 13 August 2020:05:53:27 PM


Question 355. Asked on :13 August 2020:05:51:01 PM

What is the basic use of hyteresis curve?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

nisha sheikh
The basic use of hysteresis curve lies in the selection of suitable materials for different purposes like core of transformer/generator, electromagnets, permanent magnets etc. 

-Answered by nisha sheikh On 14 August 2020:10:15:12 AM


Answer:

Shruti Srivastva
The carbon steel piece will dispate greater heat energy as its hyteresis loop has greater area.

-Answered by Shruti Srivastva On 13 August 2020:05:49:37 PM


Question 357. Asked on :13 August 2020:05:43:06 PM

What does the area of hytersis loop indicate?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
The area of the hyteresis loop gives a measure of the energy wasted in a sample when it is taken through a cycle of magnetisation.  

-Answered by Shruti Srivastva On 13 August 2020:05:43:59 PM


Question 358. Asked on :13 August 2020:05:40:48 PM

Define hyteresis.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
The phenomenon of lagging of magnetic induction behid the magnetising field in a magnetic material is called hyteresis.

-Answered by Shruti Srivastva On 13 August 2020:05:41:18 PM


Question 359. Asked on :13 August 2020:05:37:57 PM

Give two essential characterstics of a material used or preparing an electromagnet.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
(i) High permeability

(ii) Low retentivity

-Answered by Shruti Srivastva On 13 August 2020:05:39:38 PM


Question 360. Asked on :13 August 2020:05:35:03 PM

What is curie point?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
Curie point is the temperature above which a ferromagnetic substance becomes paramagnetic.

-Answered by Shruti Srivastva On 13 August 2020:05:35:54 PM


Question 361. Asked on :13 August 2020:05:33:16 PM

Will the neon gas be diamagnetic or paramagnetic?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
Paramagnetic.

-Answered by Shruti Srivastva On 13 August 2020:05:34:46 PM


Question 362. Asked on :13 August 2020:05:31:18 PM

How does the intensity of magnetisation of a paramagnetic sample vary with temperature?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva

 1T 

-Answered by Shruti Srivastva On 13 August 2020:05:32:40 PM


Question 363. Asked on :13 August 2020:05:27:21 PM

The permiability of bismuth is 0.9983. To which class of magnetic materials, does bismuth belong?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
As the permeability of bismuth is less than 1, so it is diamagnet. 

-Answered by Shruti Srivastva On 13 August 2020:05:29:23 PM


Question 364. Asked on :13 August 2020:05:24:47 PM

Relative permeability of a material µ, = 400. Identity the nature of the magnetic material.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
Ferromagnetic.

-Answered by Shruti Srivastva On 13 August 2020:05:27:08 PM


Question 365. Asked on :13 August 2020:05:22:00 PM

Relative Permability of a material has a value lying 1<µ, <1 + ∈. Identify the nature of the magnetic substances?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
Paramagnetic.

-Answered by Shruti Srivastva On 13 August 2020:05:24:21 PM


Question 366. Asked on :13 August 2020:05:21:13 PM

What is a ferromagnetic substance?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

nisha sheikh
Ferromagnetism is the basic mechanism by which certain materials (such as iron) form permanent magnets, or are attracted to magnets. ... Only a few substances are ferromagnetic. The common ones are iron, cobalt, nickel and most of their alloys, and some compounds of rare earth metals.

-Answered by nisha sheikh On 14 August 2020:10:16:23 AM


Question 367. Asked on :13 August 2020:05:19:33 PM

Which of the following substance are paramagnetic?

Bi, Al, Cu, Ca, Pb, Ni

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
Al and Ca.

-Answered by Shruti Srivastva On 13 August 2020:05:20:56 PM


Question 368. Asked on :13 August 2020:05:18:03 PM

What is a paramagnetic substance?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

nisha sheikh
Paramagnetic materials are substances which when placed in a magnetic field are feebly magnetized in the direction of the magnetizing field.

-Answered by nisha sheikh On 14 August 2020:10:18:17 AM


Question 369. Asked on :11 August 2020:06:05:36 PM

What is paramagnetic substance?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Sehnaaz Sheikh

 These are matals that are weakly attracted to magnets . They include aluminium , gold and copper . The atoms of these substances contains electrons most of which spin in the same direction .. but not all . this gives the atoms some polarity.

-Answered by Sehnaaz Sheikh On 12 August 2020:09:36:06 AM


Question 370. Asked on :11 August 2020:06:04:05 PM

Which of the following substance are diamagnetic?

             Bi, Al, Na, Cu, Ca and Ni

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
Bi and Cu.

-Answered by Shruti Srivastva On 11 August 2020:06:05:15 PM


Question 371. Asked on :11 August 2020:06:03:05 PM

What is a diamagnetic substance?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Sehnaaz Sheikh

 Diamagnetic materials are repelled by a magnetic field :in them in the opposite direction , causing a repulsive force.

-Answered by Sehnaaz Sheikh On 12 August 2020:09:40:10 AM


Question 372. Asked on :11 August 2020:06:01:20 PM

What is the one quantum of atomic dipole moment called?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
Bohr magneton.

-Answered by Shruti Srivastva On 11 August 2020:06:02:42 PM


Question 373. Asked on :11 August 2020:06:00:24 PM

Write the SI unit of magnetic induction?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
Tesla (T).

-Answered by Shruti Srivastva On 11 August 2020:06:01:02 PM


Question 374. Asked on :11 August 2020:05:58:50 PM

Write the SI unit of µ.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
Tm A-1.

-Answered by Shruti Srivastva On 11 August 2020:05:59:31 PM


Question 375. Asked on :11 August 2020:05:57:37 PM

Write the SI unit of M.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
Am-1.

-Answered by Shruti Srivastva On 11 August 2020:05:58:33 PM


Question 376. Asked on :11 August 2020:05:56:46 PM

Write the dimensions of H.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
L-1A.

-Answered by Shruti Srivastva On 11 August 2020:05:57:07 PM


Question 377. Asked on :11 August 2020:05:55:43 PM

Write the SIunit of H.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva

Am2.

-Answered by Shruti Srivastva On 11 August 2020:05:56:26 PM


Question 378. Asked on :11 August 2020:05:53:59 PM

Write the SI unit of BO.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
Tesla (T).

-Answered by Shruti Srivastva On 11 August 2020:05:55:26 PM


Question 379. Asked on :11 August 2020:05:53:21 PM

Define magnetic suspectibility.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

nisha sheikh
Physical Background. Magnetic susceptibility is the degree to which a material can be magnetized in an external magnetic field.

-Answered by nisha sheikh On 14 August 2020:10:19:07 AM


Question 380. Asked on :11 August 2020:05:52:49 PM

Define relative permeability.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

nisha sheikh
A  relative permeability is defined as the ratio of the material permeability to the permeability of free space (or vacuum), μo, and given as(17.5)μrelative=μμowhere.

-Answered by nisha sheikh On 14 August 2020:10:20:18 AM


Question 381. Asked on :11 August 2020:05:51:59 PM

Define magnetic permeagility.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

nisha sheikh
Magnetic permeability, relative increase or decrease in the resultant magnetic field inside a material compared with the magnetizing field in which the given material is located.

-Answered by nisha sheikh On 14 August 2020:10:21:13 AM


Question 382. Asked on :11 August 2020:05:51:25 PM

Define magnetisation of a material.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Anjali Kumari
 In classical electromagnetism, magnetization or magnetic polarization is the vector field that expresses the density of permanent or induced magnetic dipole moments in a magnetic material. ... Physicists and engineers usually define magnetization as the quantity of magnetic moment per unit volume.

-Answered by Anjali Kumari On 13 October 2020:07:23:20 PM


Question 383. Asked on :11 August 2020:05:51:01 PM

Define magnetic induction.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Anjali Kumari
The product of the magnetic permeability of a medium by the intensity of magnetic field in it

-Answered by Anjali Kumari On 13 October 2020:07:24:19 PM


Question 384. Asked on :11 August 2020:05:50:33 PM

Define magnetic intensity.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

nisha sheikh
 Magnetic intensity - The amount of magnetic flux in a unit area perpendicular to the direction of magnetic flow. magnetic field strengthmagnetic flux density, magnetic induction.

-Answered by nisha sheikh On 14 August 2020:10:32:10 AM


Question 385. Asked on :11 August 2020:05:48:46 PM

What is a magnetising field?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

nisha sheikh
The magnetic field is the area around a magnet in which there is magnetic force.

-Answered by nisha sheikh On 14 August 2020:10:29:44 AM


Question 386. Asked on :11 August 2020:05:46:34 PM

What is induced magnetism?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
When a piece of magnetic material is placed in a magnetic field, the material gets magnetised, The magnetism so produeced in the material is called induced magnetism.

-Answered by Shruti Srivastva On 11 August 2020:05:47:24 PM


Question 387. Asked on :11 August 2020:05:45:07 PM

Give the order of magnetic moment of an atom.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
10-23 Am2.

-Answered by Shruti Srivastva On 11 August 2020:05:46:07 PM


Question 388. Asked on :11 August 2020:05:42:14 PM

A magnet is placed with the north pole towards the north of the earth. Predict the position of the neutral points.

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
The neutral points lie on equotorial line on either side of the magnet. 

-Answered by Shruti Srivastva On 11 August 2020:05:44:08 PM


Question 389. Asked on :11 August 2020:05:41:11 PM

Define neutral point in the magnetic field of a bar magnet?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Anjali Kumari
neutral point of Magnet is a point at which the resultant magnetic field is zero. ... When the N pole of the magnet points South and the magnet in the magnetic meridian.

-Answered by Anjali Kumari On 13 October 2020:07:29:59 PM


Question 390. Asked on :11 August 2020:05:38:56 PM

What are isodynamic lines?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
The line joining the places having the same value of the horizontal componenet of earth's magnetic field are called isodynamic lines.

-Answered by Shruti Srivastva On 11 August 2020:05:39:27 PM


Question 391. Asked on :11 August 2020:05:35:29 PM

What is an aclinic line?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
The line of zero dip is calles acinic line.

-Answered by Shruti Srivastva On 11 August 2020:05:38:06 PM


Question 392. Asked on :11 August 2020:05:35:03 PM

What is isoclinical lines?

-Added by Shruti Srivastva Physics » Magnetism

Answer:

Shruti Srivastva
The lines joining the places of equal dip are called isoclinical lines.

-Answered by Shruti Srivastva On 11 August 2020:05:37:01 PM


Question 393. Asked on :11 August 2020:05:34:27 PM</