NEET2018PhysicsOscillationsActual
Assertion : If a pendulum is suspended in a lift and lift is falling freely, then its time period becomes infinite. Reason : Free falling body has acceleration equal to acceleration due to gravity.
Options
- AIf both assertion and reason are true and reason is the correct explanation of assertion.
- BIf both assertion and reason are true but reason is not the correct explanation of assertion.
- CIf assertion is true but reason is false.
- DIf both assertion and reason are false.
Correct answer
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
Step-by-step solution
If a pendulum is suspended in a lift and lift is moving downward with some acceleration a , then time period of pendulum is given by, T=2 l g-a In the case of free fall, a=g then T= i.e., the time period of pendulum becomes infinite.