A current carrying circular loop of radius R is placed in the x-y plane with centre at the origin. Half of the loop with `xgt0` is now bent so that it now lies in the y-z plane.

Options

A. The magnitude of magnetic moment now diminishes.
B. The magnetic moment does not change.
C. The magnitude of B at (0,0z), `z gt R` increases.
D. The magnitude of B at (0,0,z), `z gt gt R` is unchanges.

Answer

A

Explanation

The direction of magnetic moment of circularloop of radius R is placed in the x-y plane is along z-direction and gien by `M=I(pir^(2))`, when half of the loop with xgt0 is now bent so that it now lies in the y-z plane,t he magnitudes of magnetic moment of each semicircular loop of radius R lie in the x-y plane and the y-z plane is `M'=I(pir^(2))//4` and the direction of magnetic moments are along z-direction and x-direction respectively their resultant
`M_("net")=sqrt("M^('2)+M^('2))=sqrt(2)M'=sqrt(2)I(pir^(2))//4`.
so, `M_("net") lt M` or M diminishes.