IGCSE Physics - Magnets

Magnets

Any material capable of attracting iron and producing magnetic field outside itself

Electromagnet

Magnets that are produced due to electricity

Properties of magnets

1. Have 2 poles (north & south)
2. Exert forces on each other
3. Surrounded by magnetic field

1. If two pairs of poles that are the same (ex: North & North) meet, they will repel
2. On the other hand, different poles will attract

Magnetic interaction

Dipolar magnet

Only 2 poles are possible

The positive & negative

North = positive

South = negative

To check whether a pole is North or South

Use a compass

Types of magnets

1. Natural magnets
2. Artificial magnets

Materials that can be made into magnets

Iron, nickel, cobalt

Materials that CAN’T be made into magnets

Brass, copper, zinc, tin, aluminium, non-metals

Magnets classification

1. Ferromagnetism is a property of certain materials that results in a significant, observable magnetic permeability, and in many cases, a significant magnetic coercivity, allowing the material to form a permanent magnet. \[STRONG\]
2. Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. \[WEAK\]
3. Diamagnetic materials are repelled by a magnetic field; an applied magnetic field creates an induced magnetic field in them in the opposite direction, causing a repulsive force. In contrast, paramagnetic and ferromagnetic materials are attracted by a magnetic field. \[CANNOT BE USED FOR/ATTRACTED TO MAGNETS\]

Magnetism induced in iron

Temporary

Magnetism induced in steel

Permanent

Magnetise easily, demagnetised easily, and soft

Iron

Harder to magnetise (than iron), permanently magnetised, and a hard material

Steel

Magnetisation

the process that makes a substance magnetic (temporarily or permanently)