Question

A particle of mass $m$ is placed at the centre of a uniform spherical shell of mass $3 m$ and radius $R$. The gravitational potential on the surface of the shell is

• A. $-\frac{G m}{R}$
• B. $-\frac{3 G m}{R}$
• C. $-\frac{4 G m}{R}$
• D. $-\frac{2 G m}{R}$

Answer 1

Answer: (C)

Gravitational potential on the surface of the shell is
$V=$ Gravitational potential due to particle $\left(V_{1}\right)$
+ Gravitational potential due to shell itself $\left(V_{2}\right)$
$=-\frac{G m}{R}+\left(-\frac{G 3 m}{R}\right)$
$=-\frac{4 G m}{R}$