A square loop of edge ‘l’ and carrying a current  i, is placed with its edges parallel to the XY axes. There is  a non-uniform magnetic field present in the region  B→=B01+xl−k^. Find the magnitude of the net magnetic force experienced by the loop.

The magnetic field in the region B=B01+xlForce on AB (along -x axis),  F1=iB01+0l=iBolForce on CD (along +x axis), F2=iB01+lll=iBo.2lThe force due to wires BC (along +y axis) and AD (along -y axis) will be equal and opposite. Hence, the force on BC and AD will cancel out each other. Net force,  F2−F1=iB0l. (along +x axis)