Question

Suppose a helical spring is suspended from the roof and a very small weight is attached to its lower end. What will happen to the spring when the current is passed through it? Give reason to support your answer.

Answer 1

The spring will contract.

Reason: We know that if current passes through a wire in clockwise direction, it behaves like South pole and if it flows in anticlockwise direction, it behaves like North pole.

If we observe the enclosed figure, the current is flowing in anticlockwise direction when observed from above and clockwise if observed from below. Hence upper side will behave like north and lower like south pole. Whole of the coil will behave like N and S poles placed side by side and hence will attract each other resulting in contraction of the coil.