Magnetism Physics Test

What is magnetism?

A physical phenomenon produced by the motion of electric charges.

What is a magnet?

A material or object that produces a magnetic field.

Name three properties of magnets.

Attract ferromagnetic materials, have magnetic poles, obey the law of magnetism.

What are ferromagnetic materials?

Metals attracted to magnets e.g. iron, cobalt, nickel, and their alloys.

Where is magnetism concentrated in a magnet?

At the poles (North and South).

What is a magnetic field?

A region where a magnet or ferromagnetic object experiences a force.

Why is a plastic ball non-magnetic?

Its electron magnetic fields cancel each other out.

What are magnetic domains?

Regions where atoms’ fields align in the same direction.

How are permanent magnets formed?

Many domains align to produce a net magnetic field.

How can you magnetise an object?

Stroking with a magnet, hammering in N-S direction, or passing DC through a solenoid.

How are magnetic fields different from electric fields?

You can never find a single magnetic pole; poles always come in pairs.

What happens when like poles are brought together?

They repel each other.

What happens when unlike poles are brought together?

They attract each other.

What is the best test for magnetism?

Repulsion

What is soft iron?

Iron that is easy to magnetise and demagnetise.

What is steel in magnetism?

A hard magnetic material, difficult to magnetise and demagnetise.

How can hammering magnetise steel?

Aligns domains when hammered in Earth’s N-S direction.

How can you create an electromagnet?

Wrap a wire around a nail and connect it to a battery.

How can magnets be demagnetised?

Heating, hammering, or placing in AC current.

What do magnetic field lines represent?

The direction and strength of a magnetic field.

What does closeness of magnetic field lines indicate?

A stronger field.

What is magnetic flux?

The strength of a magnetic field.

What tool shows magnetic field direction?

A compass.

What is magnetic shielding?

Blocking a magnetic field using conductive or magnetic materials.

How do magnetic materials affect field lines?

They concentrate and redirect field lines.

Why is magnetic shielding important in MRI scanners?

To prevent external fields from interfering with the equipment.

Give four uses of magnets.

Electric motors, relays, electric bells, refrigerators.