A hollow ping pong ball with a radius of a and charge of 1 C uniformly distributed on its surface is floating in space. The electric field inside the ball is 0 N/C, as the enclosed charge is 0 C. Outside the ball, the electric field is calculated to be 88705.46 /a^2 N/C using Gauss's law. A small non-conducting ball with mass 1.0 mg and charge 2.0x10-8 C hangs from a thread at an angle of 30° from a vertical conducting sheet. The surface charge density of the sheet is calculated. A solid conducting sphere of radius a=2.00 cm with a charge of +5.00

1. ote: Draw a diagram/picture for each problem. Be sure to show all of your work for f edit. Also,
if there are physical dimensions in the answer, then your answers should h nits. [5 points]
Consider a hollow ping pong ball with a radius of a floating in space. The pin ong ball has a
charge of 1 C uniformly distributed over its surface. What is the electric fiel verywhere inside
and out of this ping pong ball? . [7 points) A small non-conducing ball of mass m 1.0 mg and
charge q 2.0x10-8 C hang ron an insulating thread that makes an angle of ? 30° with a vertical
non-conducing sheet hat extends vertically and into and out of the page. Calculate the surface
charge density ? ol he sheet. . 18 points) A solid conducting sphere of radius a 2.00 em is
concentric with a spherical onducting shell of inner radius b 2.00a and outer radius 2.40a. The
sphere has a ne uniform charge q +5.00 fC; the shell has a net charge What is the magnitude of
the electric field at radial distances (a) r 0, (b) r- a/2, (c) r a, (d) r 1.5a, (e) r-2.3a and (f) r 3.5a?
What is the net charge on the (8) inner and (h) outer surface of the shell? 4. [5 points) Space
vehicles traveling through Earth's radiation belts can intercept a significant number of electrons.
The resulting charge baild up can damage electronic components and disrupt operations.
Suppose a spherical metal satellite i 3m in diameter accumulates 2.4 of charge in one orbital
revolution. (a) Find the resulting surface charge density, (b) Calculate the magnitude of the
electric field just outside the surface of the satellite, due to the surface charge 20 DO F4
Solution
Given
ping pong ball of radius a with charge
q = 1*10^-6 C
the charge is uniformly distributed over its surface
the electric field inside the ball is zero because
from Gauss Law the electric flux is
E*A cos theta = q_in /epsilon not
here q_in = 0 C so

2. E = 0 N/C
out side is
E*A cos theta = q_in /epsilon not
E = q_in /epsilon not*4pi*a^2
E = (1*10^-6)/(8.854*10^-12*4pi*a^2) N/C
E = 88705.46 /a^2 N/C