(a) What is an electromagnet? List any two uses.

(b) Draw a labelled diagram to show how an electromagnet is made.

(c) State the purpose of soft iron core used in making an electromagnet.

(d) List two ways of increasing the strength of an electromagnet if the material of the electromagnet is fixed.

(a) Electromagnet: A temporary magnet formed when a piece of magnetic material, like soft iron, is placed inside a current-carrying solenoid coil and becomes magnetised by the strong magnetic field produced inside the solenoid.

Two uses:

1. Used in electric motors, loudspeakers, and microphones.
2. Used in industrial cranes to lift and transport heavy iron scrap and machinery.

(b) Labelled Diagram:

``diagram {"xrange": [76.0, 324.0], "yrange": [-222.0, -98.0], "polygons": [{"points": [[100.0, -110.0], [300.0, -110.0], [300.0, -140.0], [100.0, -140.0]]}, {"points": [[160.0, -190.0], [200.0, -190.0], [200.0, -210.0], [160.0, -210.0]]}], "lines": [{"from": [100.0, -125.0], "to": [100.0, -200.0], "label": ""}, {"from": [300.0, -125.0], "to": [300.0, -200.0], "label": ""}, {"from": [100.0, -200.0], "to": [160.0, -200.0], "label": ""}, {"from": [240.0, -200.0], "to": [300.0, -200.0], "label": ""}], "points": [{"x": 200.0, "y": -125.0, "label": "Soft Iron Core"}, {"x": 180.0, "y": -200.0, "label": "Battery"}, {"x": 220.0, "y": -200.0, "label": "Key (K)"}]} ``

(c) Purpose of Soft Iron Core:

1. It has high magnetic permeability, which concentrates and greatly intensifies the magnetic field lines inside the solenoid, making the electromagnet much stronger.
2. It is a temporary magnetic material, meaning it loses almost all of its magnetism as soon as the electric current is switched off, allowing the electromagnet to be turned on and off at will.

(d) Two ways to increase the strength of the electromagnet:

1. By increasing the current ($I$) flowing through the solenoid coil.
2. By increasing the number of turns ($n$) per unit length of the solenoid coil.