Two circular coils X and Y having radii R and respectively are placed in horizontal plane with their centres coinciding with each other. Coil X has a current I flowing through it in the clockwise sense. What must be the current in coil Y to make the total magnetic field at the common centre of the two coils, zero? With the same currents flowing in the two coils, if the coil Y is now lifted vertically upwards through a distance R, what would be the net magnetic field at the centre of coil Y?

. a) Two circular coils X and Y having radii R and R/2 respectively are placed in horizontal plane with their centres coinciding with each other. Coil X has a current ‘I’ flowing through it in the clockwise sense. What must be the current in the coil Y to make the total magnetic field at the common centre of the two coils , Zero ?

b) With the same currents flowing in the two coils , if the coil Y is now lifted vertically upwards through a distance R , what should be the net magnetic field at the centre of the coil