In the figure, two concentric circular loops of wire carrying current in the same direction lie in the same plane. Loop 1 has radius 1.70 cm and carries 4.40 mA. Loop 2 has radius 2.40 cm and carries 5.70 mA. Loop 2 is to be rotated about a diameter while the net magnetic field B set up by the two loops at their common center is measured. Through what angle must loop 2 be rotated so that the magnitude of the net field is 91.0 nT?

In the figure, two concentric circular loops of wire carrying current in the same direction lie in the same plane. Loop 1 has radius 1.70 cm and carries 4.40 mA. Loop 2 has radius 2.40 cm and carries 5.70 mA. Loop 2 is to be rotated about a diameter while the net magnetic field B set up by the two loops at their common center is measured. Through what angle must loop 2 be rotated so that the magnitude of the net field is 91.0 nT?