Question

Two concentric conducting spherical shells produce a radially outward electric field of magnitude 49,000 N/C at a point 4.10 m from the center of the shells. The outer surface of the larger shell has a radius of 3.75 m. If the inner shell contains an excess charge of -5.30 μC, find the amount of charge on the outer surface of the larger shell. (k = 1/4ε0 = 8.99 × 109 N · m2/C2)

Answer 1

Magnitude of the electric field just outside the outer surface is:

E = 49,000 N/C (4.10/3.75 )^2

equate this to sigma/epsilon_0 to find the surface charge density.

Answer 2

96.92