Rankers Physics

Magnetic Properties of Matter: Practice Problem & Solution

A wire of length $L\text{ m}$ carrying a current of $I\text{ A}$ is bent in the form of a circle. Its magnetic moment is: (2020-Covid)
$\pi L^2 / 4\text{ Am}^2$
$2I L^2 / \pi\text{ Am}^2$
$I L^2 / 4\pi\text{ Am}^2$
$I L^2 / \pi\text{ Am}^2$

Solution Explained:

To solve this problem, we apply the core principles of Magnetic Properties of Matter. Understanding the underlying formula is key to arriving at the correct answer below:

Radius $r = L / (2\pi)$. Area $A = \pi r^2 = L^2 / (4\pi)$. Magnetic moment $M = I A = I L^2 / (4\pi)$.

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