Problem Set 7

Due Friday, October 28, by 4pm in the homework locker

Problem 1 [10 points]
Griffiths Problem 2.43
Problem 2 [15 points]
Griffiths Problem 2.53
Problem 3 [10 points]
Griffiths Problem 3.2 - To be more specific, a charge placed in the center of the cube of charges will be accelerated away from the center if it is displaced an infinitesmally small amount in a certain direction. Find such a direction.
Problem 4 [10 points]
Consider an planar conducting slab of finite thickness D oriented perpendicular to the z axis. One side of the slab is at z=0, while the other side of the slab is at z=−D. The slab has surface area A, but you may consider A to be so large that we can ignore edge effects at the edges of the slab. The slab is constrained to be electrically neutral (i.e. the slab has no net charge). Consider now a point charge q located on the z axis in front of the slab at position z=d. Find the electric field in all regions of space, i.e. in front of the slab (z > 0), in back of the slab (z < −D), and inside the slab (−D <z <0). Solve this problem using what we learned from the method of image charges, but make sure you keep the slab neutral!
Problem 5 [10 points]
Griffiths Problem 3.11 - You should think about the last two sentences of this problem, but you do not have to give an answer to this part.