# Problem Set 02

```Physics 2220 – Module 02 Homework
01.
The cube in the figure contains negative charge. The electric field strengths in N/C are constant over
each face of the cube. Does the missing electric field vector on the front face point in or out? What
strength must this field exceed?
02.
What is the electric flux through the surface shown in the figure?
03.
How much charge is enclosed within the octahedron which has a net electric flux of -1000 N m 2/C?
04.
The electric field strength just above one face of a copper penny is 2000 N/C. What is the surface
charge density on this face of the penny?
05.
The conducting box in the figure has been given an excess negative charge. The surface density of
excess electrons at the center of the top surface is 5.0 ⨯ 1010 electrons / m2. What are the electric field
strengths E1 to E3 at points 1 to 3?
06.
A spherically symmetric charge distribution produces the electric field E = (200/r)r N/C
200
N
⃗
E=
r̂
r
C
( )
where r is in meters.
(a)
What is the electric field strength at r = 10 cm?
(b)
What is the electric flux through a 20-cm-diameter spherical surface that is concentric with the
charge distribution?
How much charge is inside the 20-cm-diameter spherical surface?
(c)
07.
An infinite slab of charge of thickness 2z0 lies in the xy-plane between z = -z0 and z = +z0. The volume
charge density is a constant.
(a)
(b)
(c)
Use Gauss's Law to find an expression for the electric field strength inside the slab.
Find an expression for the electric field strength above the slab.
Draw a graph of E from z = 0 to z = 3 z0.
```