6. Magnetism and Electromagentism

Describe construction of electromagnets?

Made from a coil of wire wrapped around an iron core.

Describe how the magnetic field pattern for a straight wire looks like?

There’s a magnetic field around a straight, current-carrying wire.

The field is made up of concentric circles with the wire in the centre.

Describe how the magentic field pattern for a flat circular coil looks like?

The magnetic field is in the centre of a flat circular coil of wire.

There’s concentric ellipses(stretched circles) of magnetic field lines around coil.

Describe how the magnetic filed pattern for a solenoid looks like?

The magnetic field inside a current-carrying solenoid is strong and uniform.

Outside the coil the field is like the one around a bar magnet.

Is there a force on a charged particle when it moves in a magnetic field?

Yes, as long as they’re not moving parallel to the field lines.

Describe the structure of a transformer?

They have 2 poles, primary and secondary, joined with an iron core.

When an alternating voltage is applied across the primary coil, the iron core magnetises and demagnetises quickly.

This induces an alternating voltage in atoms are coil.

Function of transformer?

Changes the size of an alternating current by having different number of turns on the input and output sides.

Function of step-up transformers?

Increases the voltage, has more turns is secondary coil than primary.

Function of step-down transformers?

Decreases voltage, more turns in the primary than secondary.