A particle of mass M is situated at the center of a spherical shell of same mass and radius a. The gravitational potential at a point situated at `a/2` distance from the centre, will be.......

Options

A. `-(3GM)/a`
B. `-(2GM)/a`
C. `-(GM)/a`
D. `-(4GM)/a`

Answer

A

Explanation

`implies` Potential energy at given point
= Potential energy at a given point due to shell + potenital energy at given point due to particle
`=-(GM)/a+(-(GM)/((a/2)))`
`=-(GM)/a - (2GM)/a`
`= - (3GM)/a`