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.

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true but R is not correct explanation of A

(c) A is true but R is false

(d) A and R are false

Answer 1

Correct option  (b) Both A and R are true but R is not correct explanation of A

Explanation:

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,

In the case of free fall, a = g then T = ∞ 

i .e., the time period of pendulum becomes infinite.