In the figure below, a solid sphere, of radius a = 2.90 cm is concentric with a
ID: 1528192 • Letter: I
Question
In the figure below, a solid sphere, of radius a = 2.90 cm is concentric with a spherical conducting shell of inner radius b = 2.00a and outer radius c = 2.40a. The sphere has a net charge q1 = +4.00 fC which is distributed uniformly through the sphere; the shell has a net charge of q2 = -q1.
In the figure below, a solid sphere, of radius a 2.90 cm is concentric with a spherical conducting shell of inner radius b 2.00a and outer radius c 2.40a. The sphere has a net charge q +4.00 fC which is distributed uniformly through the sphere; the shell has a net charge of q2 --q1. (a) What is the magnitude of the electric field at radial distance r 0? N/C (b) What is the magnitude of the electric field at radial distance r a/2? N/C (c) What is the magnitude of the electric field a radial distance r a? N/C (d) What is the magnitude of the electric field at radial distance r 1.40a? N/C (e) What is the magnitude of the electric field at radial distance r 2.20a? N/C (f) What is the magnitude of the electric field at radial distance r- 3.90a? N/C (g) What is the net charge on the inner surface of the shell? (h) What is the net charge on the outer surface of the shell?Explanation / Answer
from Gauss Law, E . A = Qin / e0
(A) for r = 0
Qin = 0 => E = 0
(B) r = (a/2)
Qin = q1 ((a/2)/a)^3 = q1 / 8
E ( 4 pi (a / 2) ^2) = (q1 / 8) / e0
E = q1 / (32 pi e0 (a/2)^2)
E = (4 x 10^-15 ) / ( 32 x pi x 8.854 x 10^-12 x (0.029/2)^2)
E = 0.0214 N/C
(C) r = a
E ( 4 pi a^2) = q1 /e0
E = q1 / (4 pi e0 a^2) = 0.0427 N/C
(D) E = q1 / (4 pi e0 r^2)
E = 0.0218 N/C
(E) field inside conductor is zeero.
E = 0
(F) Qin = q1 + q2 = q1 + (-q1) = 0
E = 0
(g) on inner surface = - ( q1) = - q1 = - 4 fC
(h) on outer surface = q2 - (-q1) = q2 + q1 = 0