Question

A cardboard had iron fillings spread over it and a straight current carrying conductor passes through the centre of it. When the direction of current is reversed, what happens?

• A. No change observed
• B. The iron fillings become disarranged
• C. The iron fillings arrange themselves in concentric circles but in opposite direction to the previous arrangement
• D. None of these

Answer 1

The correct option is C

The iron fillings arrange themselves in concentric circles but in opposite direction to the previous arrangement

This is because the direction of magnetic field changes when the direction of flow of current is reversed.