Question

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

Mark is an error by the council. we suggest you to use 'correct diagram' instead of 'wrong Diagram.'

(i) What is the polarity induced at the ends A and B when the switch is pressed? 

(ii) Suggest one way to strengthen the magnetic field in the electromagnet.

(iii) what will be the polarities at A and B if the direction of current is reversed in the circuit?

Answer 1

(i) Polarity induced at end A is south pole (s) and at end B is north pole (N).

(ii)The strength of magnetic field can be increased by increasing the current or by increasing the number of windings in the electromagnet.

(iii) If direction of current is reversed, the polarities at A and B will also be reversed. End A will become north pole (N) and end B will become south pole (S).