Energy required in moving a body of mass `m` from a distance 2R to 3R from centre of earth of mass M is

Options

A. `(GMm)/(12 R^(2))`
B. `(GMm)/(3R^(2))`
C. `(GMm)/(8R)`
D. `(GMm)/(4R)`

Answer

D

Explanation

Change in potential energy in displacing a body from `r_(1)` to `r_(2)` is given by
`DeltaU=GMm[(1)/(r_(1))-(1)/(r_(2))]=GMm((1)/(2R)-(1)/(4R))=(GMm)/(4R)`