Question

A magnet of magnetic moment $10\hat{i}A-m^2$ is placed along the x-axis in a magnetic field $\overline{B}=(2\hat{i}+3\hat{j})T$ . The torque acting on bar magnet is :

• A. $20\hat{i}+30\hat{k}N-m$
• B. $20\hat{k}N-m$
• C. $30\hat{k}N-m$
• D. $20\hat{i}+30\hat{j}N-m$

Answer 1

The correct option is C $30\hat{k}N-m$

The torque acting on bar magnet is given as,

$\tau =M\times B$

$\tau =\left(10\hat{i}\right)\times \left(2\hat{i}+3\hat{j}\right)$

$\tau =30\hat{k}N\cdot m$

Thus, the torque acting on bar magnet is $30\hat{k}N\cdot m$.