Q. The magnetic moment of a magnet is 0.1 amp $\times m^{2}$. It is suspended in a magnetic field of intensity$3 \times 10^{- 4}\ Wbm^{- 2}$. The couple acting upon it when deflected by 30${^\circ}$ from the magnetic field is
A) $1 \times 10^{- 5}$N m
B) 1.5 $\times 10^{- 5}$N m
C) 2 $\times 10^{- 5}$N m
D) 2.5 $\times 10^{- 5}$N m
Explanation
(b) $\tau = MB\ sin\theta = 0.1 \times 3 \times 10^{- 4}sin30{^\circ}$
$= 1.5 \times 10^{- 5}$ N-m
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.