A wire has a length of 4.52 x 10-2 m and is used to make a circular coil of one turn. There is a current of 7.94 A in the wire. In the presence of a 8.04-T magnetic field, what is the maximum torque that this coil can experience?

Answer 1

The magnitude of torque is M=p•B•sinα,
where p is the magnetic moment, B is magnetic field.
Max M=p•B.
p=I•A, where A is the area of the loop.
If the length of the wire is L=2πR, the radius is R=L/2π,
the area is A= πR^2=L^2/4 π=1.626•10-4 (m^2)
Max M= I•( L^2/4 π) •B= 7.94•1.626•10-4•8.04=0.01 N•m