5.21 A magnetic dipole is under the influence of two magnetic fields. The angle between the field directions is 60°, and one of the fields has a magnitude of 1.2 × 10–2 T. If the dipole comes to stable equilibrium at an angle of 15° with this field, what is the magnitude of the other field?


Magnitude of one of the magnetic field, B1=1.2×10-2T
Magnitude of the other magnetic field, B2
Angle between the two fields, θ=60°
At stable equilibrium, the angle between the dipole and field B1 θ1=15°
Angle between the dipole and field B2, θ2=θ-θ1=60°-15°=45°
|At rotational equilibrium, the torques between both the field
must balance each other.
Torque due to field B1=Torque due to field B2
M=Magnetic moment of hte dipole
Hence, the maanituda if tha otharmaanatic fiale is 4.39×10-3T.