Spherical shell

A spherical shell is a three-dimensional hollow structure that is shaped like a sphere. It is typically defined as the space between two concentric spherical surfaces — an outer surface and an inner surface. The shell has a certain thickness, which is the difference between the radii of the outer and inner surfaces. Key characteristics of a spherical shell include: 1. **Outer Radius (R_outer)**: The radius of the outer surface of the shell.