Show with the aid of the diagram how a wire is wound on a U-shaped piece of soft iron in order to make it an electromagnet. Complete the circuit diagram and label the poles of the electromagnet.

Figure shows the current flowing in the coil of wire wound around the soft iron horse shoe core.

(a) State the polarities developed at the ends A and B.

(b) How will the polarity at the ends A and B change on reversing the direction of current.

(c) Suggest one way to increase the strength of magnetic filed produced.

A charge moving in a magnetic field in a direction other than the direction of the magnetic field experiences a force called :

1. Lorentz force
2. Nuclear force
3. Electric force
4. Gravitational force

In fleming's left hand rule, the forefinger indicates the direction of :

1. force
2. current
3. motion
4. magnetic field