Question

A short bar magnet placed with its axis at $30^{\circ}$ with a uniform external magnetic field of $0.16\,T$ experiences a torque of magnitude $0.032\,J$ . The magnetic moment of the bar magnet will be

• A. $0.23\,JT^{-1}$
• B. $0.40\,JT^{-1}$
• C. $0.80\,JT^{-1}$
• D. zero

Answer 1

Answer: (B)

$0.40\,JT^{-1}$

Answer 2

Magnetic moment $M=\frac{t}{B\sin \theta }=\frac{0.032}{0.16\times \sin {{30}^{o}}}$ $=0.40\,\,JT^{-1}$