All the shaded areas represent conductors and the unshaded a

All the shaded areas represent conductors, and the un-shaded areas represent air. Assume that the outer sphere (Area of a sphere is 4 pi r^2) has a total charge of -5.0 mu C. The inner sphere has a charge of -2.0 mu C What is the charge on the inner surface of the bigger sphere? What is the charge on the outer surface of the bigger sphere? What is the electric field at A (radius = 0.02m)? What is the electric field at B (radius = =0.55m)?

Solution

8)

Qin = -2 uC

A) for the charge on the inner surface

charge on the inner surface = - charge placed inside the shell

charge on the inner surface = - (-2 uC)

charge on the inner surface = 2 uC

B)

charge on the inner surface + charge on the outer surface = total charge

charge on the outer surface = -5 uC - (2 uC)

charge on the outer surface = - 7 uC

the charge on the outer surface is -7 uC

C)

electric field at A = k * Qin/r^2

electric field at A = 9*10^9 * 2 *10^-6/0.02^2

electric field at A = 4.5 *10^7 N/C

D)

at electric field at B

the electric field inside the conductor is Zero