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. `(IL)/(4pi)`
B. `(I^(2) L)/(4pi)`
C. `(I^(2) L^(2))/(4pi)`
D. `(IL^(2))/(4pi)`

Answer

D

Explanation

For coil circumference `L = 2 pi r`
`therefore " " r = (L)/(2pi)`
Area of coil `= pi^(2) = pi ((L)/(2pi))^(2) = (L^(2))/(4 pi)`
Magnetic moment = IA
`rArr` Magnetic moment ` = (IL^(2))/(4pi)`