A wire of length L metre carrying a current of I ampere is bent in the form of a circle. Find its magnetic moment.

Options

A. `1pi L^(2)//4 A m^(2)`
B. `21 L^(2)//pi Am^(2)`
C. `1 L^(2)//4pi Am^(2)`
D. `1 L^(2)//4 Am^(2)`

Answer

C

Explanation

`tau = L/(2pi)` `tau = I//A = I(pir^(2)) = I(pi) (L/(2pi))^(2) =(IL^(2))/(4pi)`