Problem Set 7

Due Monday, November 2, by 2 pm in PHY 142 homework locker

You may have to wait for Tuesday's lecture to do many of these problems

Problem 1 [5 points]
Consider a square loop of side a, with current I₁, sitting a distance d awary from an infinite straight wire with current I₂ as shown in the picture below. What is the net force on the loop due to the magnetic field of the wire. Consider both the case where I₁ > 0 (current clockwise as shown) and I₁ < 0 (current counter-clockwise, opposite as shown). Be sure to give the magnitude and direction of the force.
Problem 2 [10 points]
a) Consider two infinite flat planes separated by a distance d. The planes are oriented with normal in the z direction. If the top plane has a uniform surface current density K in the x direction, and the bottom plane has a uniform surface current - K in the x direction, find the magnetic field everywhere above, below, and in between the two planes. What if the bottom plane has surface current +K in the x direction? What if the bottom plate has surface current K in the y direction?
b) Consider an infinite flat plane of finite thickness d. The plane is oriented with normal in the z direction. A uniform current density J is distributed throughout the cross-sectional area of the plane. Find the magnetic field above, below, and inside the plane.
Problem 3 [10 points]
Purcell 6.16 - assume the current is distributed uniformly over the cross-sectional area of the rod.
Problem 4 [10 points]
Purcell 6.3
Problem 5 [10 points]
Purcell 6.4
Problem 6 [5 points]
Purcell 6.12