Maximum torque and potential energy of a current loop in a magnetic field

[tag16]

Homework Statement

A wire is formed into a circle having a diameter of 10.0 cm and placed in a uniform magnetic field of 3.00 mT. The wire carries a current of 5.00 A. Find (a) the maximum torque on the wire (b) the range of potential energies of the wire field system for different orientations of the circle.

Homework Equations

T= mu x B

The Attempt at a Solution

For part a I did: T= mu x B= IA x B= I((2pi)(.5m)^2) x B
= (5.00A)((2pi)(.5m)^2) x (3.00mT)

is this right? if not what do I need to do?

For part b: I have no idea and any help would be appreciated.

 

[rl.bhat]

Check the area of the coil.