Question

A wire of length L carries a current of 1 ampere on bending it into a circle, the value of its magnetic moment will be :-

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

Answer 1

The correct option is D $I{L}^2/4\pi$

R.E.F image

Solution Magnetic moment $\left(\mu \right)=NAI$

$\pi =\left(1\right)\left(\pi r^2\right)I$

$\pi =\left(1\right)\left[\pi \right(\frac{l}{2\pi }{)}^2]I$

$\pi =\frac{l^{2}I}{4\pi }$

Option - D is correct