SCIENCE FORM 2 CHAPTER 7 (7.3)

CHAPTER 7:

Electricity and magnetism

7.3 MAGNETISM

MAGNET

Characteristics of a Magnet

(a) A magnet has two poles – the north and the
south poles.
(b) The same poles repel, different poles attract
each other.
(c) A free hanging magnet always points in the

north-south direction.
(d) A magnet can attract iron, steel, cobalt and
nickel.

A magnetic field

• Magnetic filed: the area around the magnet
with magnetic force.

• Neutral point: space that does not have any
magnetic field.

Attract to
the magnet

DRAW!!!

Located in area around the magnet
with magnetic force as known as

MAGNETIC FIELD

X

DRAW!!!

NEUTRAL POINT

FREE FROM THE EFFECT OF
MAGNETIC FORCE

The characteristics of
magnetic field lines

1. The magnetic field lines begin from the north
pole and end at the south pole.

2. The magnetic filed lines are closer to one
another where the magnetic filed is stronger.

3. The magnetic field lines never meet or across.

MAGNETIC FIELD LINES

DRAW!!!

Electromagnet

1. An electromagnet is a type of magnet that has
temporary magnetic effect when electric
current flow through it.

PATERN OF MAGNETIC FORCE
(CIRCULAR CIRCLE-STRAIGHT WIRE)

DRAW!!!

PATERN OF MAGNETIC FORCE
(CIRCULAR CIRCLE - SOLENOID COIL)

DRAW!!!

PATERN OF MAGNETIC FORCE
(SOLENOID – BAR MAGNET)

DRAW!!!

‘ RIGHT-HAND GRIP RULE’

• The direction of DRAW!!!
the magnetic
field depends on
the direction of
the current
flowing in the
wire.

DRAW!!!

Application of magnets and
electromagnets in daily life

ELECTROMAGNET CRANE
Used to transport iron or the steel

Application of magnets and
electromagnets in daily life

COMPASS
always point to the
earth north pole

Application of magnets and
electromagnets in daily life

LOUD SPEAKER
change the electric
current to sound

Application of magnets and
electromagnets in daily life

ELECTRIC BELL
to turn on the ringing bell

Application of magnets and
electromagnets in daily life

BULLET TRAIN
produce the force to move it

Application of magnets and
electromagnets in daily life

MAGNET ON
THE DOOR
ensure the
door can
open/close