Potential energy of a satellite having mass `m` and rotating at a height of `6.4xx10^(6)m` from the earth surface is

Options

A. `4mgR_(e)`
B. `-2mgR_(e)`
C. `-0.5mgR_(e)`
D. `-mgR_(e)`

Answer

C

Explanation

`P.E.=-(GMm)/(r )=-(GMm)/(R_(e)+h)=-(GMm)/(2R_(e))`
`therefore U=(-gR_(e)^(2)m)/(2R_(e))(because GM=gR_(e)^(2))`
`=-(1)/(2)mgR_(e)=-0.5mgR_(e)`