=3×10−5J The magnetic field at the centre of the loop B, BB=
µ0IB
2r
=
4π×10−7×4
2×0.02×π
=4×10−5T Since, loops A and B are placed at right angles, thus magnetic field BA and BB are perpendicular to each other. Thus, net magnetic field B=√BA2+BB2 =√(3×10−5)2+(4×10−5)2 =5×10−5T