Question

A long thin magnet of moment `M` is bent into a semi circle. The decrease in the magnetic moment is
A. `2M//pi`
B. `piM//2`
C. `M(pi-2)//pi`
D. `M(2-pi)//2`

Answer 1

Correct Answer - C
For semi circle, `M^(1)=(2M)/(pI)`
decrease in `M,DeltaM=M-M^(1)`