# To study variation of time period of a simple pendulum r of a given length by taking bobs of same size but different masses and interpret the result - Physics Practical Class 11 Viva Questions with Answers

1. What is a pendulum?
2. Answer. A pendulum is a freely hanging weight suspended from a pivot.

3. Define the pendulum effect.
4. Answer. It is the movement of the object in a direction where the object in another direction feels an equal movement.

5. A simple pendulum demonstrates which type of motion?
6. Answer. A simple pendulum demonstrates periodic motion.

7. What is the formula to find the time period of a pendulum?
8. Answer. The time period of a pendulum is given by the formula:

$$\begin{array}{l}2\pi \sqrt{\frac{l}{g}}\end{array}$$

9. Define the length of a pendulum.
10. Answer. The gap between the centre of the bob and the point of suspension gives the length of a pendulum.

11. What is the mass present at the end of a thin cord of a pendulum known?
12. Answer. The mass present at the end of a thin cord of a pendulum is known as the bob.

13. State true or false: Changing the length of the pendulum changes its period.

15. Longer length pendulums swing with a smaller frequency. What would be the period?
16. Answer. They would have a longer period.

17. Does the mass on a pendulum affect the swing?
18. Answer. The mass on a pendulum does not affect the swing of the pendulum.

19. Does the changing weights and distance affect the swing?
20. Answer. Changing the weights and the distance pulled to swing has no effect on the time taken to finish a swing from an initial to the final position.

21. As per the law of the pendulum, state the law of mass.
22. Answer. The law of mass states that the time period of a pendulum is independent of the hanging weight.

23. Define damping.
24. Answer. The opposition to free vibrations of bob in a simple pendulum due to the presence of air around it is known as damping.

25. Define a seconds pendulum.
26. Answer. A pendulum whose time period is two seconds is called a seconds pendulum.

27. Name the pendulum that is not affected by a change in the ‘g’ value.
28. Answer. A spring pendulum has no effect on its time period due to a change in the value of g.

29. Define the amplitude of a simple pendulum.
30. Answer. The amplitude of a simple pendulum is the distance travelled by the pendulum from the equilibrium position to one side.

31. Are the pendulums used in clocks?
32. Answer. Yes, pendulums are used in clocks.

33. What is the formula to find the potential energy of a simple pendulum?
34. Answer. The potential energy of a simple pendulum is given by the formula: PE=

$$\begin{array}{l}mgl (1-cos\Theta)\end{array}$$

35. What is the formula to find the kinetic energy of the pendulum?
36. Answer. The formula to find the kinetic energy of the pendulum is

$$\begin{array}{l}\frac{1}{2}mv^{2} \end{array}$$
.

37. Explain how the mechanical energy of a simple pendulum is conserved.
38. Answer. Mechanical energy = Kinetic energy + potential energy

=

$$\begin{array}{l}\frac{1}{2}mv^{2} \end{array}$$
+
$$\begin{array}{l}mgl (1-cos\Theta)\end{array}$$
= constant

39. Does a change in the temperature affect the time period?
40. Answer. Yes. If the temperature of a system varies, the time period of the pendulum also varies since the length of the pendulum changes.