Question

Question 5.21: A magnetic dipole is under the influence of two magnetic fields. The angle between the field directions is 60º, 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 15º with this field, what is the magnitude of the other field?

Class 12 - Physics - Magnetism And Matter Magnetism And Matter Page-203

Answer 1

Given ,
magnitude of magnetic field, B = 1.2 × 10^-2T
angle between dipole and field direction is 60°
finally, dipole comes stable equilibrium at an angle of 15° .

magnetic dipole moment experiences torque due to both the field and is in equilibrium.
e.g., $MB_1sin\theta_1=MB_2sin\theta_2$
so, 1.2 × 10^-2 × sin60° = $B_2$ × sin15°
$B_2$=0.44 × 10^-2 T