Given figure shows a coil bent with all edges of length `1 m` and carrying a current of `1 A`. There exists in space a uniform magnetic field of `2 T` in positive y-direction. Find the torque on the loop.

Explanation

The forces on the edges FG and BC are zero. The forces on the other edges are :
`F_(AB)=Bil(hati)`
`F_(CD)=Bil(-hati)`,
`F_(HG)=Bil(-hati)`
`F_(EF)=Bil(hati)`,

The torque of forces `F_(AB)` and `F_(HG)` is zero and that of `F_(CD)` and `F_(EF)` is zero.
The forces on edges AH and DE are equal and opposite and so constitutes a net torque. Thus
`F_(AH)=Bil(-hatk)` and `F_(DE)=Bil(hatk)`
Torque `=Bil^(2)=2.1.1hati=2hatiN-m`