Electromagnetism

Demonstrating magnetic field in a conductor current carrying

• A large coil with many turns of insulated copper wire is set up vertically with one of its vertical side passing through a hole in the centre of a piece of a cardboard supported horizontally.
• Current is passed through the coil
• A fine layer of iron filings is then sprinkled on the cardboard and is taped gently. Iron filings set in a series of concentric circles about the wire.
• A small compass placed on the card indicates the direction of the field

Magnetic field in a long straight conductor

• The magnetic field of a straight current-carrying conductor can be investigated using apparatus shown in diagram above.
• The field of a straight current-carrying conductor is a set of concentric circles around the wire. The field direction depends on the current direction Magnetic field due to a coil

When an electric current is passed through a solenoid (coil) the resultant magnetic field is similar to that of a bar magnet. It acts as a magnet when current flows through it