If the earth shrinks such that its density becomes `8` times to the present values, then new duration of the day in hours will be

Options

A. 96 hours
B. 48 hrs
C. 6 hrs
D. 1.5 hrs

Answer

D

Explanation

By conservation of angular momentum `I_(1) omega_(1)= I_(2) omega_(2)`
`rArr (2)/(5) MR^(2) (2pi)/(T) = (2)/(5)M ((R)/(4))^(2) (2pi)/(T)`
`T.= (T)/(16)= (24)/(16)= 1.5` hrs