Question:
A mass of $50 \mathrm{~kg}$ is placed at the centre of a uniform spherical shell of mass $100 \mathrm{~kg}$ and radius $50 \mathrm{~m}$. If the gravitational potential at a point, $25 \mathrm{~m}$ from the centre is $\mathrm{V} \mathrm{kg} / \mathrm{m}$. The value of $\mathrm{V}$ is :
Correct Option: , 4
Solution:
$\mathrm{V}_{\mathrm{A}}=\left[-\frac{\mathrm{GM}_{1}}{\mathrm{r}}-\frac{\mathrm{GM}_{2}}{\mathrm{R}}\right]$
$=\left[-\frac{50}{25} \mathrm{G}-\frac{100}{50} \mathrm{G}\right]$
$=-4 \mathrm{G}$