Question

Two circular coils mounted parallel to each other on the same axis carry steady currents. If an observer between the coils reports that one coil is carrying a clockwise current $i_1$ while the other is carrying a counter-clockwise current $i_2$ , then the two coils experience

• A. a steady repulsive force
• B. zero force
• C. a repulsive force
• D. a steady attractive force

Answer 1

Answer: (D)

The coil carrying a current $i$ in clockwise sense coil has south polarity on that face of coil and other coil having current $i_2$ in counter clockwise sense has north polarity on that face of the coil. As south and north poles will attract each other, hence a steady attractive force acts between the two coils.