A "bar" magnet of moment `M` is cut into two identical pieces along the length. One piece is bent in the form of a semi circle. If two pieces are perpendicular to each other, then resultant magnetic moment is

Options

A. `(M//pi)^(2)+(M//2)^(2)`
B. `sqrt((m//pi)^(2)+(M//2)^(2))`
C. `sqrt((m//pi)^(2)-(M//2)^(2))`
D. Zero

Answer

B

Explanation

`M'=sqrt(M_(1)^(2)+M_(2)^(2))`
`=sqrt(((2m)/(2pi))^(2)+((M)/(2)))=sqrt(((M)/(pi))^(2)+((M)/(2))^(2))`