A magnet of length `2L` abd moment `'M'` is axially cut into equal halves `'P'` and `'Q'`. The piece `'P'` is bent in the form of semi circle and `'Q'` is attached to it as shown. Its moment is

Options

A. `M/pi`
B. `M/(2pi)`
C. `(M(2+pi))/(2pi)`
D. `(Mpi)/((2+pi))`

Answer

C

Explanation

In the arrangement magnetic moment of P is `M_(1)=(2M/2"sin"pi/2)/pi=M/pi` and magnetic moment of Q is `M_(2)=M/2therefore` Resultant magnetic moment
`M_(r)=M_(1)+M_(2)=M/pi+M/2=(M(pi+2))/(2pi)`