Q. If two identical bar magnets, each of length $l,$ pole strength m and magnet moment M, are placed perpendicular to each other with their unlike poles in contact, the magnetic moment of the combination is
A) $\frac{M}{\sqrt{2}}$
B) $lm\left( \sqrt{2} \right)$
C) $2lm\left( \sqrt{2} \right)$
D) 2M
Explanation
(b) When magnet are placed perpendicular to each other then,
Resultant magnetic moment
$\ \ \ \ \ \ \ \ \ \ \ \ \ M^{'} = \sqrt{M_{1}^{2} + M_{2}^{2}}$
Here, $M_{1} = M_{2} = M$
$So,\ \ \ \ \ \ \ M' = M\sqrt{2} = ml\sqrt{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.