Two concentric coils X and Y of radii 16cm and 10cm respectively lie in the same vertical plane containing the north south direction coil X has 20 turns and carries a current of 16A coil Y has 25 turns and carries a current of 18A the sense of the current in X is anticlockwise an in Y clockwise for an observer looking at the coils facing west give the magnitude and direction of the net magnetic field due to the coils at their centre.