Question

A point charge of -3.00 μC is located in the center of a spherical cavity of radius 6.80 cm inside an insulating spherical charged solid. The charge density in the solid is 7.35 × 10^−4 C/m^3.

Calculate the magnitude of the electric field inside the solid at a distance of 9.50 cm from the center of the cavity.

Answer 1

The electric field at this distance will be due to the total enclosed charge, as per Gauss's theorem.

Here, the enclosed charge will be the sum of the point charge and the charge due to the enclosed volume of the sphere.

This will be total charge enclosed by a Gaussian surface drawn at the distance we have to find the field at.

Since we only need the magnitude, we can neglect the sign of the charge.