Gravitation Question 78
Question: 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:
A) If both assertion and reason are true and the reason is the correct explanation of the assertion.
B) If both assertion and reason are true but reason is not the correct explanation of the assertion.
C) If assertion is true but reason is false.
D) If the assertion and reason both are false.
E) If assertion is false but reason is true.
Show Answer
Answer:
Correct Answer: A
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\pi \sqrt{\frac{l}{g-a}}] $ . In the case of free fall, $ [a=g] $ then $ [T=\infty ] $ i.e., the time period of pendulum becomes infinite.
