Question

A conducting spherical shell has inner radius r1 = 7.0 cm, outer radius r2 = 12.0 cm. A +3 uC point charge is placed at the center. A charge of Q=+4 uC is put on the conductor.

a) What is the charge on the inner and outer surface of the shell?

b)What is the electric field on the inside and outside of the shell?

Answer 1

here,

r1 = 7 cm = 0.07 m

r2 = 12 cm = 0.12 m

qA = 3 uC

Q = 4 uC

a) charge on the inner surface of the shell = - qA

charge on the inner surface of the shell = -3 uC

charge on the outer surface of the shell = 4 - 3

charge on the outer surface of the shell = 1 uC

b)

Now , inside the shell

electric field = k * qA/r1^2

electric field = 9*10^9 * 3 *10^-6/.07^2

electric field = 5.51 *10^6 N/C

outside the shell

electric field = k * charge on outside shell/r1^2

electric field = 9*10^9 * 1 *10^-6/.12^2

electric field = 6.25 *10^5 N/C