Question: A thick spherical shell made of conducting metal has inner radius R1 = 0.200 m and outer radius R2= 0.300 m. The shell has a net charge of q1=7 x 10^-9 C. At the center of the hollow space inside the shell there is a very small sphere that has charge q2=+3.0 x 10^-9 C.

Part A: What is the magnitude of the resultant electric field at a distance of r 0.500 m from the center of the shell?

I need help to find the magnitude of the resultant electric field at a distance of r 0.500 m from the center of the shell.