What is the magnitude of magnetic field at the centre O of loop of radius2 m made of uniform wire when a current of 1 A enters in the loop and is taken out of it by two long wires as shown in figure?

Since length NWP is 3 times that of NQP, so resistance of NWP is 3 times that of NQP Hence I1I2=13Net field due to I1 and I2 at centre O will be zero. Field at O due to MN will be same as that due to PQ, but in opposite direction, so net field at centre will be zero.