If the ice on the polar caps of the earth melts and water collected about equator, how will that affect the duration of a day?

Options

A. Day becomes short
B. Length of day cannot change
C. Day becomes long
D. Length of day and night becomes same

Answer

C

Explanation

When the ice on polar caps of earth melts and water collected about equator, then the moment of inertia increased `(r_("polar")ltr_("equator"))`
Since external torque on earth is not acting, its angular momentum remains constant
`therefore omega_(1)I_(1)=omega_(2)I_(2),I_(2)ltI_(2)`
`{:(omega_(1)gtomega_(2),|,"Periodic time for one"),(therefore (2pi)/(T_(1))gt(2pi)/(T_(2)),"revolution increases and",),(therefore T_(2)gtT_(1),"hence length of day increase",):}`