Question

Magnetic moment of a single-turn current loop of aluminium wire of area A, carrying a current I in a wire of diameter d is

• A. IAd
• B. $\mu$IA
• C. IA/d
• D. IA

Answer 1

Answer: (D)

IA

Answer 2

The magnetic moment ($\vec{\mu}$) of a current loop is defined as the product of the current (I) flowing through the loop, the area (A) enclosed by the loop, and the number of turns (N). It is a vector quantity, with its direction perpendicular to the plane of the loop, given by the right-hand thumb rule.

The formula for the magnitude of the magnetic moment is: $\mu = NIA$

In this question, we are given:

1. A single-turn current loop, which means $N = 1$.
2. The area of the loop is $A$.
3. The current flowing through the loop is $I$.

Substituting these values into the formula: $\mu = (1) \times I \times A$ $\mu = IA$

The information about the material (aluminium wire) and the diameter of the wire ($d$) is extraneous for calculating the magnetic moment of the loop, given the current and the area. These details would be relevant if we were to calculate resistance or other properties, but not for the magnetic moment itself.

The correct option is IA.