Question

When a straight magnetised wire of magnetic moment $M$ is bent into a $U$ shape such that all the parts are of equal lengths, then final magnetic moment is $M/3$.

• A. True
• B. False

Answer 1

The correct option is A True

Let the original length be $3l$ therefore the magnetised wire of magnetic moment $M_1=m\ast \left(3l\right)=3M$

then the when all the parts are of equal lenght,$M_2=m\ast l_1=\frac{m\ast l}{3}=\frac{M}{3}$