The diagram shows a coil wound around a U shape soft iron bar AB

The diagram shows a coil wound around a U shape soft iron bar AB.

1. What is the polarity induced at the ends A and B when the switch is pressed?
2. Suggest one way to strengthen the magnetic field in the electromagnet.
3. What will be the polarities at A & B if the direction of current is reversed in the circuit?

Answer

1. South and south.
2. Increasing the strength of current through the coil.
3. The polarities at the two ends become North.