Question

A wrist watch keeps correct time on earth. If it is shifted to the surface of moon
Then it
${\text{A}}{\text{.}}$ loses time
${\text{B}}{\text{.}}$ gains time
${\text{C}}{\text{. }}$keeps correct time
${\text{D}}{\text{.}}$ does not function

Answer 1

Hint: Here in this question we have to care about watch because whenever we see this type of question we think about change in acceleration due to gravity and in our mind simple pendulum concepts remember but here it is wrist watch and here there is no pendulum so no effect of acceleration due to gravity occurs.

Complete answer:
We have given in question
A wrist watch keeps correct time on earth. If it is shifted to the surface of moon Then it
Here in this question we have to care about watch because whenever we see this type of question we think about change in acceleration due to gravity and in our mind simple pendulum concepts remember but here it is wrist watch and here there is no pendulum so no effect of acceleration due to gravity occurs.
That means there will be no change in time so wrist watches will show accurate time on the moon also.
Hence we conclude that wrist watches are always accurate.
But if we get questions regarding the wall watch in which the pendulum is attached. Then we have to care about everything and then acceleration due to gravity matters and we do all the changes according to the time period of the simple pendulum.

So, the correct answer is “Option C”.

Note:
Whenever we get this type of question the key concept of solving we have to care about which watch is given and if question related to simple pendulum then we must remember formula of time period $T = 2\pi \sqrt {\dfrac{l}{g}} $ where l is length of pendulum and g is acceleration due to gravity.