# 11th Class Physics Public Answer Key

Physics subject of 11th class is a very easy and interesting subject from which we can gain knowledge a lot. If we understand it, it’s a very easy subject. Physics is just a natural process. It is based on experiments, mathematical analysis etc. 11th class physics will be very useful in higher studies for all. So here now we are going to discuss about the 11th class physics answer key.

## Choose the correct option

1. Identify the unit vector in the following:
2. The range of sound that the human audible wavelength (speed of sound in air = 340 ms-1) is
3. a) 17m to 170m b) 0.17m to 17m c) 0,017m to 17m d) 1.7m to 17m

4. A column of air in a tube, closed at one end, resonates with an object vibrating 83 Hz. Then the length of the air column (speed of sound in air = 332 ms-1)
5. a) 1.5m b) 0.5m c) 2.0m d) 1.0m

6. Rms speed of hydrogen molecule at 27C
7. Which one of the following in a scalar quantity
8. a) Speed b) velocity c) displacement d) linear momentum

9. Body length measured 3.51 m. If the accuracy is 0.01 m, the percentage measurement error is
10. a) 0.035% b) 351% c) 1% d) 0.28%

11. An object with mass of 20 kg, moving at a speed of 10 ms-1 on a horizontal smooth surface, collides with a massless spring with a constant spring of 5 N / m. When the mass stops after the impact, the compression distance of the spring is
12. a) 10m b) 50m c) 5m d) 20m

13. When a car takes a sudden left turn on a curved road, passengers are pushed towards the right due to
14. a) Absence of inertia b) inertia of direction c) inertia of motion d) inertia of rest

15. The efficiency of a heat engine working between the freezing point and boiling point of water is
16. a) 12.5% b) 6.25% c) 20% d) 26.8%

17. A spring with a force constant k is cut in half so that the length of one part is twice the length of the other. Then the longer piece has a force constant of
18. The dimensional formula for moment of inertia
19. The ratio between the rms speed and most probable speed of gas molecules at a given temperature
20. If the distance between the earth and sun is twice its present value, the number of days in a year will be
21. a) 730 b) 1032 c) 64.5 d) 182.5

22. Moment of inertia of a solid cylinder of mass M, length l and radius r about its own axis is

### 11th Class Physics Public Answers:

1. A
2. C
3. D
4. B
5. A
6. D
7. D
8. B
9. D
10. C
11. D
12. B
13. B
14. D

#### Conclusion:

These are the 11th class physics key papers. Which is very important. It is one of the key papers that will be very useful for everyone in higher studies. Everyone should practice these objective problems. It’s very important.