Download 4 Electromagnetism

New Senior Secondary Physics at Work
Teaching Scheme
4
Book 4
Electricity and Magnetism
No. of periods: 84*
Electromagnetism
Topic
4.1 Magnetic field
Core
1
2
3
Extension
Magnets
Magnetic fields
The earth’s magnetic field
No. of
periods*
2
Experiment
(Practical Workbook)
4a Magnetic field
patterns
Example
1
2
Identify the magnetic
bars
Bar magnets
Exercises
Banknote
Activity 4a
Check-point 1
Practice 4.1
4.2 Magnetic field
of electric currents
1
Magnetic field due to electric current
a Field around a straight wire
(Apply B 
0I to represent the
2r
magnetic field around a long
straight wire)
b Field around a circular coil
(Apply B 
0I
2r
6
4b Magnetic fields from
currents
4c Electromagnets
3
4
5
6
Resultant magnetic
field
Magnetic field of a
solenoid
Magnetic effect of a
coil
Ding-dong door bell
Electromagnetic
lock
Check-point 2
Check-point 3
Check-point 4
Teaching aids
Simulation
4.1 Magnetic field
Video
4.1 Banknote with magnet
4.2 Expt 4a - Magnetic field
patterns
4.3 3D magnetic field
pattern
Simulation
4.2 Magnetic field around a
long straight wire
Video
4.4 Expt 4b - Magnetic
fields from currents
4.5 Expt 4c Electromagnets
Practice 4.2
to represent the
magnetic field at the centre of a
flat circular coil)
c Field due to a long solenoid
(Apply B 
0NI
I
to represent the
magnetic field at the centre of a
long solenoid)
2
3
Electromagnets
Applications of electromagnets
a Magnetic levitation (Maglev) train
b Electric bells and buzzers
c Telephones
© Oxford University Press 2010
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New Senior Secondary Physics at Work
4.3 Current
-carrying conductor
in a magnetic field
1
Force on a current-carrying conductor
a Fleming’s left-hand rule
b Factors affecting magnetic force
8
(Represent the force on a straight
current-carrying wire by
F = BIl sin θ)
c Magnetic force between two
parallel currents
2
4d Force on a
current-carrying
conductor
4e Effect of current on
magnetic force
4f Effect of magnetic
field strength on
magnetic force
4g Constructing a
model electric motor
4h Investigating factors
that affect the turning
effect on a coil
Application: electric motors
a Turning effect on a coil
b Simple d.c. motors
c Factors affecting the turning effect
on coils
3
Deflection of electron
in a magnetic field
Battery car
Practice 4.3
Simulation
4.3 Turning effect on a coil
4.4 Simple d.c. motor
4.5 Working principle of a
loudspeaker
Video
4.6 Expt 4d - Force on a
current-carrying
conductor
4.7 Expt 4e - Effect of
current on magnetic
force
4.8 Expt 4f - Effect of
magnetic field on
magnetic force
4.9 Expt 4g - Constructing
a model electric motor
4.10 Expt 4h - Investigating
factors that affect the
turning effect on a coil
DIY corner
simple electric motor
How fast does
the puck move?
Video
4.11 Expt 4i - Measuring
magnetic fields with
Hall probe
Check-point 5
8
Measuring force
using a digital
balance
9 Calculation of
magnetic force
10 Interaction between
two parallel
current-carrying
wires
Check-point 6
Check-point 7
Check-point 8
11 Rotations of a coil
12 Battery car
13 Factors affecting the
turning effects of
coils
14 Measuring magnetic
field using a current
balance
d Practical motors
Application: moving-coil loudspeakers
4.4 Hall effect
7
1
2
3
4
5
Electric current as
flow of electric
charges
Drift velocity and
current
Magnetic force on a
moving charge
Hall voltage
a Explanation of Hall
effect
b Derivation of Hall
voltage
c Characteristics of
conductors
revealed by Hall
voltage
Measuring magnetic
fields by a Hall probe
5 + 2 (for
problem
solving
and
revision)
4i
Measuring magnetic
fields with Hall probe
15 Nerve conduction
16 An electron under
both magnetic and
electric fields
17 Finding the number
of charge carriers
and drift velocity
18 Hall voltage in
different materials
19 Circular motion of an
electron beam
Check-point 9
Check-point 10
Check-point 11
Practice 4.4
Revision
exercise 4
Total = 23
Chapter Quiz
4-4
* The time allocation does not include the time for ‘Investigative Study’. 24 periods should be allocated to inquiry-oriented activities (project work, presentation,
written report, article reading etc.) throughout the whole course. See the notes in the Teaching Scheme of Chapter 1 for more details.
© Oxford University Press 2010
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