A circular loop of wire having a radius of `8.0 cm` carries a current of `0.20 A`. A vector of unit length and parallel to the dipole moment W of the loop is given by `0.60 hati-0.80 hatj` . if the loop located in uniform magnetic field given by `B= (0.25 T)hati+ (0.30 T)hatk` find,
(a) the torque on the loop and
(b) the magnetic potential energy of the loop.

Explanation

`:'=M=iA=i(piR^2)`
`=(0.2)(pi)(8xx10^-2)^2`
`-(4.0xx10^-3)A-m^2`
Now, `M=MhatM=(4.0xx10^-3)(0.6hati-0.8hatj)`
a. `tau=MxxB`
b. `U=-M.B`