UPSEE Solved Model Paper 1

Two identical wires ‘A’ and ‘B’ each of length ‘ℓ’ carry the same current I. Wire A is bent into a semicircle of radius ‘R’ and wire B is bent to form a square of side ‘a’. If BA and BB are the values of magnetic field at the centers of the semi-circle and square respectively, then the relation between BA and BB is–