Magnetism

Which metals are magnetic?

Iron, steel, nickel and cobalt.

What is a permanent magnet?

A magnet that produces its own magnetic field.

What do permanent magnets always do?

Exert a force on other magnets.

What shapes can permanent magnets be?

Bar magnets and horseshoe magnets.

What is an induced magnet?

A material that becomes magnetic only in a magnetic field.

What happens to induced magnets when removed from the field?

They lose their magnetism.

How do induced magnets interact?

They can only be attracted, not repelled.

What are iron filings used for?

Showing magnetic field patterns.

What is a magnetic field?

The region around a magnet where a force acts on another magnet or magnetic material.

How do you test a permanent magnet?

It will attract or repel another permanent magnet.

How do you detect a magnetic field using a compass?

Place a plotting compass near the magnet.

What is the first step in plotting magnetic field lines?

Place the magnet on paper and put a compass nearby.

What do you do after placing the compass?

Mark the direction the needle points.

What is the next step in plotting field lines?

Move the compass and repeat marking directions.

Final step in plotting field lines

Join the points to show field lines.

What is the Earth's core mainly made from?

Iron and nickel.

What causes Earth's magnetic field?

Convection currents in the core.

Do magnetic field lines cross?

No, they never cross.

What do closer field lines indicate?

A stronger magnetic field.

What do arrows on field lines show?

Direction of the magnetic force.

What direction do magnetic field lines go?

From north to south.

What happens when current flows through a wire?

A circular magnetic field forms around it.

What happens to magnetic field strength near a wire?

It is stronger closer to the wire.

What happens if current increases?

The magnetic field strength increases.

What effect does a current-carrying wire have on a compass?

It can deflect the needle.

What is a solenoid?

A coil of wire carrying current.

What does a solenoid produce?

A strong, uniform magnetic field.

Why is a solenoid's field strong?

Each coil's magnetic field combines to strengthen it.