What would be the duration of a day on the earth if it shrinks to half of its size all of a sudden?

Text Solution

If both assertion and reason are true and reason is the correct explanation of assertion.If both assertion and reason are reason are true but reason is not the correct explanation of assertion.If assertion is true but reason is falseIf both assertion and reason are false.

Answer : A

Solution : (a) When earth shrinks its angular momentum remains constant i.e., <br> `L = I omega = (2)/(5) mR^2 xx (2 pi)/(T) = constant` <br> `T prop I prop R^2` it means if size of earth changes then its moment of inertia changes <br> If radius is half so time period will become `T//4`/ hence `24//4 = 6 Hr`.