A current of `5A` is flowing through a 10 turns circular coil of radius `7cm`. The coil lies in x-y plane. What is the magnitude and direction of dipole moment associated with it?
If this coil were placed in a uniform external magnetic field directed along the x-axis, in which plane would be coil lie in equilibrium?
`pi=22//7`.

Explanation

Here, `I=5A, N=10, r=7xx10^-2m`
`M=NIA=NI(pir^2)`
`=10xx5xx22/7(7xx10^-2)^2=0*77Am^2`
The direction of `vecM` is perpendicular to the plane of the coil, along Z-axis.
Torque on the current loop, `tau=MB sin theta`
where `theta` is angle between `vecM` and `vecB`.
For stable equilibrium, `tau=0 :. theta=0^@`.
Hence `vecB` should be perpendicular to plane of the coil. Hence in the condition of stable equilibrium, coil will be in Y-Z plane.