A wire of length l, carrying current i, is bent in circle of radius r, then magnetic moment at centre of loop is

Options

A. `Il^(2)//2pi`
B. `Il^(2)//4pi`
C. I
D. l

Answer

B

Explanation

`M=IA=Ipir^(2),Now l=2pir therefore r=(1)/(2pi)`
Thus ,`M=(Ipir^(2))/(4pi^(2))=(Il^(2))/(4pi)`