A wire of length `L metre ` , carrying a current `I `ampere is bent in the form of a circle . The magnitude of its magnetic moment is …………. ` MKS units ` .

Options

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

Answer

B

Explanation

If the radius of circle is `r`, then `2pir=Limpliesr=(L)/(2pi)`
Area `=pir^(2)=(piL^(2))/(4pi^(2))=(L^(2))/(4pi)`
Magnetic moment `= IA=(IL^(2))/(4pi)`