Question

A bar magnet of moment $M$ is bent into a shape as shown in the given figure, with all segments equal. It's new magnetic moment will be :

• A. $\frac{M}{\sqrt{3}}$
• B. $\frac{M}{\sqrt{5}}$
• C. $\frac{M}{\sqrt{2}}$
• D. $\frac{2M}{\sqrt{3}}$

Answer 1

Answer: (B)

$\frac{M}{\sqrt{5}}$

Magnetic Length $=L/\sqrt{5}$
because Magnetic Moment is directly proportional to Magnetic Length
$\therefore M^{\prime }=M/\sqrt{5}$