Simple pendulum and dissipation of energy — NEET & JEE Questions

Question 1 · difficulty L1 · recall

For small oscillations, the time period of a simple pendulum is approximately

• A. T=2πsqrt(g/L)
• B. T=L/g
• C. T=2πsqrt(L/g)
• D. T=2πL/g

Question 2 · difficulty L1 · understanding

The period of a simple pendulum is approximately independent of

• A. pendulum length
• B. local g
• C. large amplitude outside the small-angle limit
• D. bob mass

Question 3 · difficulty L2 · understanding

If pendulum length is quadrupled, its small-angle period becomes

• A. twice
• B. four times
• C. half
• D. unchanged

Question 4 · difficulty L2 · application

To reduce timing reaction error in a pendulum experiment, one should time

• A. only a fraction of one oscillation
• B. many oscillations and divide by their number
• C. one oscillation repeatedly without averaging
• D. the bob mass

Question 5 · difficulty L2 · understanding

In a real simple-pendulum experiment, the amplitude gradually decreases mainly because

• A. air resistance and friction dissipate mechanical energy
• B. gravity steadily becomes weaker
• C. the bob loses mass on every swing
• D. the string becomes perfectly elastic

Question 6 · difficulty L3 · application

Damping causes pendulum amplitude to

• A. increase indefinitely
• B. remain exactly constant in air
• C. decrease with time
• D. reverse sign permanently after each cycle

Question 7 · difficulty L3 · application

In a damped pendulum, lost mechanical energy is mainly converted into

• A. extra gravitational potential that accumulates forever
• B. mass
• C. electric charge
• D. thermal energy and sound in the surroundings

Question 8 · difficulty L3 · application

A pendulum is released from a small angle and its successive maximum heights decrease. What happens to its mechanical energy?

• A. It decreases with time
• B. It increases with time
• C. It remains exactly constant
• D. It becomes negative

Question 9 · difficulty L3 · application

If frictional effects in a pendulum experiment are reduced, the oscillations should

• A. persist for a longer time before dying out
• B. stop more quickly
• C. have zero period
• D. become independent of gravity

Question 10 · difficulty L4 · analysis

A graph of amplitude versus time for a lightly damped pendulum is expected to show

• A. a gradually decaying envelope
• B. constant amplitude forever
• C. linear growth without bound
• D. instantaneous zero after one cycle