P4.1 Simple phenomena of magnetism

Question 1

Forces between magnetic poles

Answer 1

Different poles like N pole to S pole attracts, while same pole like N pole to N pole or S pole to S pole repels.

Question 2

Forces between magnets and magnetic material

Answer 2

• Magnets and unmagnetised magnetic material attracts
• Magnets and magnetised magnetic material can either attract or repel, if same pole then repel, different poles then attract.

Question 3

Differences between properties of temporary magnets and properties of permanent magnets

Answer 3

-Temporary magnets is a magnetic material that becomes temporarily magnetised (made of soft iron)
=> allows them to lose magnetism quickly after the external magnetic field is removed and can be magnetised and unmagnetised easily.
- Permanent magnets are magnetised magnetic material that produces its own magnetic field that does not get weaker with time
=> <ade of hard magnetic material (e.g steel) to allow it to retain its magnetism over a long period of time.

Question 4

The difference between magnetic and non-magnetic materials

Answer 4

• Magnetic material also called as Ferromagnetic material is a material that is attracted to magnets and can be magnetised
  e.g Iron, Cobalt, Nickel, Steel (mix of carbon and iron)
• Non-magnetic material is a material that is unaffected by magnets and cannot be magnetised.
  e.g Aluminium, Copper, Silver, Gold,…

Question 5

Describe how a permanent magnet differs from an electromagnet

Answer 5

• A permanent magnet is a piece of magnetised steel and will remain its magnetism over a long period of time => Hard to demagnetise it.
• Electromagnet is a coil of wire wrapped around a soft iron core, and when a current flows in the coil, it becomes a magnet.
  =>When no current flows in the wire, the whole device becomes unmagnetised.
  => Can be able to magnetised or demagnetised

Question 6

Definition of a magnetic field

Answer 6

A region in which a magnetic pole experiences a force

Question 7

Definition of magnetic field direction

Answer 7

The direction of force on a N Pole of a magnet at that point.

Question 8

Definition of Induced magnetism

Answer 8

When a magnetic material is only magnetised when placed in a magnetic field