Q. A bar magnet of magnetic moment M is bent in ‘⊔’ shape such that all the parts are of equal lengths. Then new magnetic moment is

(a) M/3

(b) 2M

(c) √3 M

(d) 3√3 M

Ans: (a)

Sol:

When a thin bar magnet of magnetic moment M is bent in the form of ⊔- shape with the arms of equal length , then

Magnetic moment of Each part = M/3

Net magnetic moment of the combination,

$ \displaystyle \vec{M’} = \frac{M}{3}(-\hat{j}) + \frac{M}{3}(\hat{i}) + \frac{M}{3}(\hat{j})$

M’ = M/3