Question

Same current is flowing in two identical coaxial circular coils. On looking at the coils from a point at the centre between them, the current in one coil appears to be flowing in clockwise direction. If the two coils at displaced towards each other, then the value of current:

• A. in each coil will decrease
• B. in each coil will increase
• C. in each coil will remain unchanged
• D. nothing can be predicted

Answer 1

The correct option is A in each coil will decrease

As the same current flows in both the coils in the same direction, upon displacing them towards each other, the flux linkage between them increases. By Lenz's law the the induced current in both the coils will be such that it opposes this increase in the flux. Hence to reduce this increase in flux, the current in both the coils will decrease.