If the mass of earth is M, radius R and G is universal gravitational constant then the workdone against gravity to move a body of mass 1 kg from the surface of earth to infinity will be

Options

A. `sqrt((GM)/(2R))`
B. `(GM)/R`
C. `sqrt((2GM)/R)`
D. `(GM)/(2R)`

Answer

B

Explanation

`implies` The potential energy of 1 kg weight on the surface of earth .
`=(-GM)/(R)`
at infinity = 0
work = change in potential energy =` (GM)/R`