A current of 30.0 mA is maintained in a single circular loop of 3.0o0 m circumference. A magnetic field of 0.850 T is directed parallel to the plane of the loop. (a) Calculate the magnetic moment of the loop. If you know the circumference of a circle, how do you find the area? mA• m2 (b) What is the magnitude of the torque exerted by the magnetic field on the loop? mN . m

A current of strength I=1a flows through the copper wire. The wire consists of two straight parts between points A(1,2,3)cm and B(1,3,2)cm and between points B and C(2,1,3)cm. The wire is located in a homogeneous magnetic field of induction B=1T. a) If the total force on the wire is 0, calculate the direction of the magnetic field. b) If we rotate the direction of the magnetic field so that the total force on the wire is the largest, calculate the maximum possible force on the wire.

The coil in the figure carries current i = 1.60 A in the direction indicated, is parallel to an xz plane, has 4 turns and an area of 3.01 x 10-3 m2, and lies in a uniform magnetic field B = (1.75i - 3.57j - 3.03k) mT. (a) What is the magnetic potential energy of the coil-magnetic field system? (b) What is the magnetic torque (in unit-vector notation) on the coil?

As shown in the figure below, two long parallel wires (1 and 2) carry currents of I1 = 3.26 A and I2 = 4.75 A in the direction indicated.   (a) Determine the magnitude and direction of the magnetic field at a point midway between the wires (d = 10.0 cm). magnitude      µT direction      ° counterclockwise from the +x-axis (b) Determine the magnitude and direction of the magnetic field at point P, located d = 10.0 cm above wire 1. magnitude      µT direction      ° counterclockwise from the +x-axis