Moving Charges and Magnetism

Magnetic field at the centre of the loop A,
BA‌=‌

µ0IA

2r

‌=‌

4π×10−7×3

2×0.02×π

‌=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