Question

When a bar magnet turned into a semicircle, its magnetic dipole moment becomes $M_0$. Now this magnet turns into quarter circle, the new magnetic moment will be

• A. $M_0$
• B. $2M_0$
• C. $2\sqrt{2}{M}_0$
• D. $\sqrt{2}{M}_0$

Answer 1

The correct option is C $2\sqrt{2}{M}_0$

hen a bar magnet tuned into a semicircle

Its magnetic dipole moment$=M_0$

Let, Magnetic moment

$M=M_0\times 2l$

Radius of the semicircle $=R$

$\pi R=2l\Rightarrow =\frac{2l}{\pi }$

When the magnet is bent in the form of a semi circle, the distane beteen the poles

$=2R$

$=2\times \left(\frac{\sqrt{2}l}{\pi }\right)=2\sqrt{2}l$

Now, magnetic moment $=2\sqrt{2}{M}_0$