A magnetic dipole is under the influence of two magnetic fields the angle between the two field directions is  600 and one of the fields has a magnitude of  1.2X10-2T. If the dipole comes to stable equilibrium at an angle of 15°  with this field, what is the magnitude of the other field?

Given  B1=1.2×10−2TInclination of dipole with  B1 is θ1=15°Therefore Inclination of dipole with   B2 is θ2=60°-15°=45°  As the dipole is in equilibrium the torque on the dipole due to the two fields are equal and opposite. If  M is the magnetic dipole moment of the dipole, then ∴MB1sinθ1=MB2sinθ2⇒B2=B1sinθ1sinθ2⇒B2=1.2×10-2×sin15°sin45o=1.2×10-2×0.25880.707⇒B2=4.39×10-3T