Question

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 x 10^-2 If the dipole comes to stable equilibrium at an angle of 15° with this field, what is the magnitude of the other field?

Answer 1

B₁ = 1.2 × 10^-2 T
Inclination of the dipole with Blθ = 15°
Therefore, inclination of the dipole with B₂
θ₂ = 60 - 15 = 45°
As the dipole is in equilibrium; the torque on the dipole due to the filed B₁ is equal and opposite to that due to B₂. If M is the magnetic dipole moment of the dipole, then,
MB₁ sinθ₁= MB₂ sinθ₂