Gravitation Part 1

The uniform spherical shell is shown in the figure below Inside the shell, there is no mass, so by applying Gauss’s law forgravitation $\oint g \cdot d a = -4\pi G M_{\text{enclosed}}$ where, g = gravitational field intensity. da = area enclosed G = gravitational constant and $M_{\text{enclosed}} =$ mass enclosed . As, $M_{\text{enclosed}} = 0$ So, gravitational field intensity is zero inside the shell, i.e. g = 0 …(i) We also know that, $g = -\frac{dV}{dr}$ where, dV is change in potential due to gravity ⇒ V = constant [using Eq. (i)] So, gravitational field is zero everywhere inside the shell and gravitational potential (V) is constant everywhere.