# 5.7 (b) A bar magnet of magnetic moment $1.5 JT^{-1}$ 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)?

For case (i):

$\theta$ = $\theta_2$ = 90°

We know, Torque, $\tau = MBsin\theta$
$= (1.5)(0.22)sin90^{\circ}$
= 0.33 J

Forcase (ii):

$\theta$ = $\theta_2$ = 180°

We know, Torque,

$\tau = MBsin\theta$
$= (1.5)(0.22)sin180^{\circ}$
= 0

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