Question

A bar magnet of magnetic moment $ M_{1} $ is axially cut into two equal parts. If these two pieces are arranged perpendicular to each other, the resultant magnetic moment is $ M_{2} $ . Then the value of $ M_{1}/M_{2} $ is

• A. $ \frac{1}{2\sqrt{2}} $
• B. $ 1 $
• C. $ \frac{1}{\sqrt{2}} $
• D. $ \sqrt{2} $

Answer 1

Answer: (D)

When magnet is cut axially, new magnetic moment of each part
$M_{1}=\left(\frac{M}{2}\right) l=\frac{M}{2}$
On placing both the parts perpendicularly.
$M_{2}=\sqrt{(M')^{2}+(M')^{2}}=\frac{M}{\sqrt{2}} $
$\therefore \frac{M_{1}}{M_{2}}=\sqrt{2}$