Q. A wire of length $L$ metre carrying a current of $I$ ampere is bent in the form of a circle. Its magnetic moment is,

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A wire of length $L$ metre carrying a current of $I$ ampere is bent in the form of a circle. Its magnetic moment is,

Solution:

$2pi,r=L$

$r=frac{L}{2pi}$

$M=I (A)$

$M=I (pi,r^{2})$

$M=I left(piright) left(frac{L}{2pi}right)^{2}$

$M=frac{IL^{2}}{4pi}$