Question

A pendulum clock keeping correct time is taken to high altitudes,
(a) it will keep correct time
(b) its length should be increased to keep correct time
(c) its length should be decreased to keep correct time
(d) it cannot keep correct time even if the length is changed.

Answer 1

Using the formula,

Time Period (T) = 2π√(l/g)

Time period of the simple pendulum changes due to change in acceleration.

Note ⇒ In the  spring-mass system, T does not depends upon acceleration.

Acceleration due to gravity only changes  as we move at high altitudes and it decreases.

since, g decreases, this means Time Increases.

Now, Time Increment can be controlled only if length of the pendulum is decreased.

If length is decreased, then ratio l/g is constant and hence the watch will give the correct time.

Hence, Option (c). is correct.

Hope it helps .

Answer 2

Answer:

ans is (c) it's length should be decreased to keep correct time