Solving a problem in physics section 51 paragraph 64 el

64. Wire coil radius R = 20 centimeters is located in the plane of the magnetic meridian. At the center of the loop with a small magnetic needle, which is able to rotate around a vertical axis. At what angle deflected arrow, but if you round to put current of I = 12 A? The horizontal component of the earth´s magnetic field induction to take in equal = 20 mT.