#### Important 2mark

11th Standard

Reg.No. :
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Physics

Use blue pen Only

Time : 01:00:00 Hrs
Total Marks : 66

Part A

33 x 2 = 66
1. What is meant by Range of masses?

2. What is clock? Write the principle and its types.

3. The resistance R = ${V\over I}$ , where V = 100 ± 5 V and I = 10 ± 0.2 A.Find the percentage error in R

4. State the number of significant figures in the following 400

5. State the number of significant figures in the following 0.0006032

6. Define acceleration.

7. What is meant by frame of reference?

8. A boy is running on a circular track of radius 50 m. Calculate the displacement of the boy after completing 5 rounds of the track.

9. Two vectors are given as $\vec r=2\hat i+3\hat j+5\hat k$ and $\vec F=3\hat i-2\hat j+4\hat k$ Find the resultant vector $\vec { \tau } =\vec { r } \times \vec { F }$.

10. What is average acceleration?

11. What is the source of centripetal acceleration for earth to go round the sun?

12. Define inertia of motion.

13. "Force and motion acts in the same direction". Give example.

14. Why are wheels of automobiles made circular?

15. An object of mass 10 kg moving with a speed of 15 ms-1 hits the wall and comes to rest within (a) 0.03 second (b) 10 second. Calculate the impulse and average force acting on the object in both the cases.

16. Why is it difficult to walk on a sand?

17. Consider two objects of masses 5 kg and 20 kg which are initially at rest. A force 100 N is applied on the two objects for 5 second.
(a) What is the momentum gained by each object after 5s?
(b) What is the speed gained by each object after 5s?

18. Why does a pilot not fall down, when his aeroplane loops a vertical loops?

19. The potential energy of a spring when stretched through a distance x is 10J. What is the amount of work done on the same spring to stretch it through on additional distance x?

20. Can a body have energy without momentum?

21. The earth moving around the sun in a circular orbit is acted upon by a force and hence work must be done on the earth. Do you agree with this statement?

22. When a work is said to be done? Give some example.

23. Two bodies of identical masses with 2nd body at rest collides with 1st body, prove that the velocities of the bodies are reversed.

24. Some heavy boxes are to be loaded along with some empty boxes on a cart. Which boxes should be put on the cart first and why?

25. A cat is able to land on its feet after a fall. Why?

26. Give examples where the centre of mass coincides with the geometrical centre of the body.

27. Are moment of inertia and radius of gyration of a body constant quantities?

28. Which physical quantity is conserved when a planet revolves around the sun?

29. Why there are two propellers in a helicopter?

30. Assume that you are in another solar system and provided with the set of data given below consisting of the planets’ semi-major axes and time periods. Can you infer the relation connecting semi-major axis and time period?

Planet
(imaginary)
Time period(T)
(in year)
Semi major axis (a)
(in AU)
Kurinji 2 8
Mullai 3 18
Marutham 4 32
Neithal 5 50
Paalai 6 72
31. Suppose unknowingly you wrote the universal gravitational constant value as G = 6.67 x 1011 instead of the correct value G = 6.67 x 1011, what is the acceleration due to gravity g' for this incorrect G? According to this new acceleration due to gravity, what will be your weight W'?

32. An object is thrown from Earth in such a way that it reaches a point at infinity with non-zero kinetic energy [K.E(r=$\infty$)= ${1\over 2}MV_{\infty}^2$], with what velocity should the object be thrown from Earth?