Asked/Added Questions From NCERT:

Question 1. Asked on :09 July 2020:06:15:38 PM

Under what condition can an object in motion the considered a point object?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

An object can be considered a point object if its size is much smaller than the distance travelled by it.

-Answered by Shruti Srivastva On 09 July 2020:06:15:59 PM

Question 2. Asked on :08 July 2020:06:40:10 PM

Write example of gravitational force?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Anjali Kumari
The force that holds the gases in the sun.

-Answered by Anjali Kumari On 15 October 2020:07:35:34 PM

Question 3. Asked on :08 July 2020:06:39:12 PM

Write important properties of gravitational force?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Anjali Kumari
The gravitational force is directly proportional to the product of the mass of the two bodies. This means a larger mass will yield a larger force. Property 3: The force obeys the inverse square law. The force is inversely proportional to the square of the distance between them.

-Answered by Anjali Kumari On 15 October 2020:07:47:06 PM

Question 4. Asked on :08 July 2020:06:30:55 PM

What are advantages of SI?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

It is a metric, rational, coherent, and internationally acceptable system of units which covers all branches of physics.

-Answered by Shruti Srivastva On 08 July 2020:06:31:32 PM

Question 5. Asked on :08 July 2020:06:30:24 PM

What is coherent system?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Anjali Kumari
A coherent system of units is a system of units, used to measure physical quantities, which are defined in such a way that the equations relating the numerical values expressed in the units of the system have exactly the same form, including numerical factors, as the corresponding equations directly relating the quantities.^[1]^[2] Equivalently, it is a system in which every quantity has a unique unit, or one that does not use conversion factors.

-Answered by Anjali Kumari On 15 October 2020:07:49:51 PM

Question 6. Asked on :08 July 2020:06:29:08 PM

Name the two supplementary of SI unit?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

Radian and Steradian.

-Answered by Shruti Srivastva On 08 July 2020:06:29:54 PM

Question 7. Asked on :08 July 2020:06:27:07 PM

Name the basic seven SI unit?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

Metre, Kilogram, Second, Ampere, Kelvin, Candela, Mole.

-Answered by Shruti Srivastva On 08 July 2020:06:27:50 PM

Question 8. Asked on :08 July 2020:06:26:45 PM

What is system of unit?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Anjali Kumari
A system of units is a set of related units that are used for calculations. ... For example, in the MKS system, the base units are the meter, kilogram, and second, which represent the base dimensions of length, mass, and time, respectively. In this system, the unit of speed is the meter per second.

-Answered by Anjali Kumari On 15 October 2020:07:51:06 PM

Question 9. Asked on :08 July 2020:06:26:09 PM

What are fundamental units?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Anjali Kumari
One of a set of unrelated units that form the basis of a system of units. For example, the metre, kilogram, and second are fundamental units of the SI system

-Answered by Anjali Kumari On 15 October 2020:07:51:47 PM

Question 10. Asked on :08 July 2020:06:24:34 PM

What is relationship between the numerical value and the size of the unit?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Anjali Kumari
The numerical value (n)of a physical quantity is inversely proportional to size of unit (u) being used to measure it. Statement-2:The magnitude of physical quantity does not change by changing the units.

-Answered by Anjali Kumari On 18 October 2020:06:53:05 PM

Question 11. Asked on :08 July 2020:06:23:34 PM

What are physical quantities?

-Added by Shruti Srivastva Physics » Units And Measurements

Question 12. Asked on :08 July 2020:06:20:25 PM

What are derived quantity?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

The physical quantities whose defining operations are based on other physical quantities are called derived quantities.

-Answered by Shruti Srivastva On 08 July 2020:06:21:59 PM

Question 13. Asked on :08 July 2020:06:06:34 PM

Write two examples of non dimensional constants?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

π,e.

-Answered by Shruti Srivastva On 08 July 2020:06:07:30 PM

Question 14. Asked on :08 July 2020:06:05:38 PM

Write the name of three dimensional constants?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

Gravitational constant, Planck's constant and Boltxmann's constant.

-Answered by Shruti Srivastva On 08 July 2020:06:08:19 PM

Question 15. Asked on :08 July 2020:06:04:59 PM

Give two examples of non-dimensional variable?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

Specific gravity and strain.

-Answered by Shruti Srivastva On 08 July 2020:06:12:43 PM

Question 16. Asked on :08 July 2020:06:02:53 PM

A junior research fellow takes 100 careful readings in an experiment. If he repeats the same experiment by taking 500 readings, then by what factor will the probable error be reduced?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

Specific Gravity and strain.

-Answered by Shruti Srivastva On 08 July 2020:06:09:17 PM

Question 17. Asked on :08 July 2020:06:00:08 PM

What importance is attached to the final zeroes in a number without any decimal point?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

All such zeroes are not significants For example 86,400 has three significant figures.

-Answered by Shruti Srivastva On 08 July 2020:06:11:05 PM

Question 18. Asked on :08 July 2020:05:58:50 PM

What is the difference between the measurements 4.0 cm and 4.000 cm?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

(i) 4.0 cm has two significant figures while 4.000 cm has four significant figures.

(ii) 4.0 cm is correct upto first decimal place while 4.000 cm is correct upto third place of decimal.

-Answered by Shruti Srivastva On 08 July 2020:06:13:38 PM

Question 19. Asked on :08 July 2020:05:57:43 PM

Give name of a scalar quantity and a vector quantity which have same dimensions?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

speed.

-Answered by Shruti Srivastva On 08 July 2020:06:16:54 PM

Question 20. Asked on :08 July 2020:05:56:27 PM

What are the dimensions of rate of flow?

-Added by Shruti Srivastva Physics » Units And Measurements

Question 21. Asked on :08 July 2020:05:53:52 PM

Which of the following has the same dimensions as Plank's constant : Torque, gravitational constant and angular momentum?

-Added by Shruti Srivastva Physics » Units And Measurements

Question 22. Asked on :08 July 2020:01:47:50 PM

State the principle of homeginety of dimensions?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

The principle of homeginetyu of dimensions states that a physical equation will be dimensionally correct if the dimensions of all the terms occuring on both sides of the equations are the same.

-Answered by Shruti Srivastva On 08 July 2020:01:48:45 PM

Question 23. Asked on :08 July 2020:01:45:00 PM

Define dimensions of a physical quantity.

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

The dimensions of a physical quantity are the powers to which the fundamental quantities must be raised to represent that quantity complete.

-Answered by Shruti Srivastva On 08 July 2020:01:46:13 PM

Question 24. Asked on :08 July 2020:01:43:28 PM

Express 0.00000538 in power of 10.

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

5.38 X 10^-6.

-Answered by Shruti Srivastva On 08 July 2020:01:44:29 PM

Question 25. Asked on :08 July 2020:01:40:54 PM

The radius of the sun is 696 000 000 m. Express it is scientific notation .

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

6.96 X 10⁸m.

-Answered by Shruti Srivastva On 08 July 2020:01:42:14 PM

Question 26. Asked on :08 July 2020:01:38:48 PM

The density of wood is 0.5 cm^-3. Write the value in SI units.

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

Density = 500 kg m^-3.

-Answered by Shruti Srivastva On 08 July 2020:01:40:05 PM

Question 27. Asked on :08 July 2020:01:37:34 PM

Name the year in which there is total solar eclipse.

-Added by Shruti Srivastva Physical Education » Units And Measurements

Answer:

Shruti Srivastva

Tropical year.

-Answered by Shruti Srivastva On 08 July 2020:01:38:31 PM

Question 28. Asked on :08 July 2020:01:35:17 PM

What is leap year?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

Leap year is the year which is divisible by 4. The February month of a leap year has 29 days.

-Answered by Shruti Srivastva On 08 July 2020:01:35:47 PM

Question 29. Asked on :08 July 2020:01:27:34 PM

Define SI unit on luminous intensity?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

One candela is defined as the luninous intensity, in a given direction, of a source than emits a mochromatic radiaton of frequency 540 X 10¹² hertz and has a radiant intensity in that direction of 1/683 watt per sterdian.

-Answered by Shruti Srivastva On 08 July 2020:01:28:32 PM

Question 30. Asked on :08 July 2020:01:23:05 PM

Name the SI unit of tempreature?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

Kelvin.

-Answered by Shruti Srivastva On 08 July 2020:01:24:00 PM

Question 31. Asked on :08 July 2020:01:12:04 PM

How many times is millisecond larger than a microsecond?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

1 millisecond = 10^-3 microsecond.

-Answered by Shruti Srivastva On 08 July 2020:01:13:58 PM

Question 32. Asked on :08 July 2020:12:56:54 PM

What is the smallest mass measured indirectly so far?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

One second is defined as the duration of 9192, 631, 770 vibrations corresponding to the transition between two hyperfine levels of cesium-133 atom in the ground state.

-Answered by Shruti Srivastva On 08 July 2020:12:58:13 PM

Question 33. Asked on :08 July 2020:12:51:52 PM

Express teregram in kg.

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

1 Teregram = 10⁹kg.

-Answered by Shruti Srivastva On 08 July 2020:12:52:25 PM

Question 34. Asked on :08 July 2020:12:49:43 PM

Express teregram in gram?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

1 Teregram = 10¹²g.

-Answered by Shruti Srivastva On 08 July 2020:12:50:49 PM

Question 35. Asked on :08 July 2020:12:37:48 PM

Define atomic mass unit.

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

One atomic mass unit is the mass of 1/12th of the mass of an atom of carbon-12 isotope.

-Answered by Shruti Srivastva On 08 July 2020:12:38:42 PM

Question 36. Asked on :08 July 2020:12:29:31 PM

Express light year in lmetre?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

1 light year = 0.946x10¹⁶m.

-Answered by Shruti Srivastva On 08 July 2020:12:30:12 PM

Question 37. Asked on :07 July 2020:06:40:34 PM

Name the device used for measuring directly the lengths to an accuracy of 10^-5m.

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

Screw gange.

-Answered by Shruti Srivastva On 07 July 2020:06:42:58 PM

Question 38. Asked on :07 July 2020:06:38:59 PM

Name the device used for measuring directly the lengths to an accuracy of 10^-4m.

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

Vernier callipers.

-Answered by Shruti Srivastva On 07 July 2020:06:42:14 PM

Question 39. Asked on :07 July 2020:04:47:18 PM

Express one micron in metre.

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

One micron is one millionth part of a metre.

-Answered by Shruti Srivastva On 07 July 2020:04:48:03 PM

Question 40. Asked on :07 July 2020:04:38:07 PM

Express parasec in metres?

-Added by Shruti Srivastva Chemistry » Units And Measurements

Answer:

Shruti Srivastva

1 parasec= 3.08 X 10¹⁶m

-Answered by Shruti Srivastva On 07 July 2020:04:38:51 PM

Question 41. Asked on :07 July 2020:04:28:56 PM

Define light year and express it in meter?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

One light is defined as the distance traveled by light in one year.

-Answered by Shruti Srivastva On 07 July 2020:04:29:52 PM

Question 42. Asked on :07 July 2020:02:00:55 PM

Why was metre redefined in terms of velocity of light in 1983?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

Because of the tremendous accuracy achieved in the measurement of time, metre has been redefined in terms of velocity of light since 1983.

-Answered by Shruti Srivastva On 07 July 2020:02:02:49 PM

Question 43. Asked on :07 July 2020:01:55:50 PM

Define standard metre in terms of velocity of light.

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

Standard metre is defined as the distance which contains 1650,763.73 wavelengths of certain orange-red radiation emitted by Kr-86 atom in its transition between 2p₁₀and 2d₅levels.

-Answered by Shruti Srivastva On 07 July 2020:01:57:16 PM

Question 44. Asked on :07 July 2020:01:50:11 PM

Define a prototype meter.

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

In 1899, the general conference of weights and measures defined metre as the distance between two transverse lines marked on a platinum-iridum rod preserved at a consonant temperature af 273.16 K at 1 bar pressure an the International Burea of Weights and Measures at Serves, near Paris in France.

-Answered by Shruti Srivastva On 07 July 2020:01:51:11 PM

Question 45. Asked on :07 July 2020:01:35:57 PM

What is a physical unit?

-Added by Shruti Srivastva Physics » Units And Measurements

Answer:

Shruti Srivastva

The standard amount of a physical quantity chosen to measure the physical quantity of the same kind is called a physical quantity.

-Answered by Shruti Srivastva On 07 July 2020:01:39:05 PM

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