2020 Phase-2 Moving Charges and MagnetismMagnetic Dipole Moment of Current Loop Medium Question 2 of 5 in Magnetic Dipole Moment of Current Loop

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

A $\dfrac{IL^2}{4\pi}\ A\,m^2$
B $\dfrac{IL^2}{4}\ A\,m^2$
C $\dfrac{IL^2}{\pi}\ A\,m^2$
D $\dfrac{2IL^2}{\pi}\ A\,m^2$

The answer is A.

Solution

Circumference $L=2\pi r\Rightarrow r=\dfrac{L}{2\pi}$. Magnetic moment $M=I\times\pi r^2=I\pi\left(\dfrac{L}{2\pi}\right)^2=\dfrac{IL^2}{4\pi}$.

Concept Magnetic moment of a current-carrying circular loop

Magnetic Dipole Moment of Current Loop in past papers

5 questions from this chapter have appeared across 5 exam years.