Question

A bar magnet of magnetic moment 1.5 J T^-1 lies aligned with the direction of a uniform magnetic field of 0.22 T.

What is the torque on the magnet in cases (i) and (ii)?

Answer 1

For case (i): `theta = theta_2 = 90°`

`therefore "Torque"  tau = "MB sin"  theta`

`= 1.5 xx 0.22  "sin"  90°`

`= 0.33  "J"`

For case (ii): `theta = theta_2 = 180°`

`therefore "Torque", tau = "MB  sin"  theta`

`= "MB sin"  180° = 0  "J"`