Q. A magnet of magnetic moment $M$ and pole strength $m$ is divided in two equal parts, then magnetic moment of each part will be
A) $M$
B) $M/2$
C) $M/4$
D) $2M$
Explanation
(b) If cut along the axis of magnet of length $l$, then new pole strength $m^{'} = \frac{m}{2}$ and new length $l^{'} = l$
$\therefore$ New magnetic moment $M^{'} = \frac{m}{2} \times l = \frac{ml}{2} = \frac{M}{2}$
If cut perpendicular to the axis of magnet, then new pole strength $m^{'} = m$ and new length, $l^{'} = l/2$
$\therefore\ $ New magnetic moment $M^{'} = m \times \frac{l}{2} = \frac{ml}{2} = \frac{M}{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.