Question Pre-1.2: Two concentric metal shells are shown in figure Pre-2: The inner shell has a radius of 1 cm and is at 100 volts, the outer shell has a radius of 2 cm and is at 200 volts. The region between the metal surfaces is charge free and air. Express Laplace's equation in spherical coordinates. Indicate which derivatives of the potential function will be zero and why they are zero. Solve the remaining differential equation and plot several equipotential lines for the region between the metal shells. Draw the electric field lines. 1 mark