Magnets
Electromagnetic
Magnetic Induction
NOT all metals are magnetic
Magnetic Materials

Permanent magnets will always have a magnetic properties

Eg, Ferrous materials such as Iron

Temporary magnets will have magnetic properties only when they are under
the influence of magnetic fields
Making a magnet by stroking
Single Touch
Divided Touch
Methods of Magnetisation
Making a magnet by stroking
Single Touch
Methods of Magnetisation
Making a magnet by using
electricity
Methods of Demagnetisation
Methods of demagnetising magnets
1. Heating
- misalignment of “tiny” magnets, increase vibration
of atoms
2. Hammering
Methods of Demagnetisation
Methods of demagnetising magnets
3.
Alternating Current
Magnetic Fields & the
Plotting Compass
A magnetic field is the region where a magnetic force is
exerted on any magnetic object placed within the
influence of the field.
Magnetic Fields & the
Plotting Compass
Magnetic Fields & the
Plotting Compass
Magnetic Fields & the
Plotting Compass
X: neutral point
Magnetic Fields & the
Plotting Compass
Earth’s Magnetic Field
Magnetic Field in wires
Sample question
 How
much magnetic field would the metal
experience if they are placed 1.2m away from
the current carrying 2 A.
 Ans
= 3.3 x 10^-7 T
Electromagnets
Strength of Electromagnet

3 Factors that affect the strength of electromagnet

1) Increase the Number of turns

2) Increase the current