A particle of mass M is situated at the centre 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:

Explanation

The gravitatioN/Al potential at the point P due to the particle at the centre is
`V_1=-(GM)/(a/2)=-(2GM)/a`
the potential at P due to the shell is
`V_2=(GM)/a`
The net potential at P is `V_1+V_2=-(3GM)/a`.