Question

A wire of length L meter carrying a current of I ampere is bent in the form of a circle. Its magnitude of magnetic moment will be

• A. $\frac{IL}{4\pi }$
• B. I$L^2$/4$\pi$
• C. $I^2{L}^2$/4$\pi$
• D. $IL/2\pi$

Answer 1

The correct option is B I$L^2$/4$\pi$

If the radius of circle is r, then 2$\pi$r=L$\Rightarrow$r=L/2$\pi$
Area= ${\mathrm{\pi r}}^2$
$\Rightarrow$$L^2/4\pi$
Magnetic Moment=IA
$\Rightarrow$$I{L}^2/4\pi$