Question

A loop of irregular shape, of area 10^-5 m² , carries a current of 8A. The flow of current appears to be clockwise to an observer. The magnetic moment of current loop is

(1) 0.8 x 10^-4 Am² and is directed away from the observer

(2) 0.8 x 10^-4 Am² and is in the plane of the loop

(3) 0.8 x 10^-4 Am² and is directed towards the observer, perpendicular to the plane of the loop

(4) 0.8 x 10^-4 Am² and is directed away from the observer perpendicular to the plane of the loop

Answer 1

(4) 0.8 x 10^-4 Am² and is directed away from the observer perpendicular to the plane of the loop

Magnetic moment of a current loop is M = (iA)\(\hat{n}\)

∴ |M| = 8 x 10^-5 Am² = 0.8 x 10^-4 Am²

From right hand rule, the direction, of M, is away from the observer and perpendicular to the plane of the loop.