A loop carrying current `I` lies in the ` x-y ` plane as shown in the figure . The unit vector ` hat k` is coming out of the plane of the paper . The magnetic moment of the current loop is

Options

A. `a^(2)Ihatk`
B. `(pi/2+1)a^(2)Ihatk`
C. `-(pi/2+1)a^(2)Ihatk`
D. `(2pi+1)a^(2)Ihatk`

Answer

B

Explanation

Area`=a^(2)+4xxpi((a)/(2))^(2)/2`
`=a^(2)+(pia^(2))/2`
`A=(1+pi/2)a^(2)hatk`