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Do now!
Can you continue with the
‘Draw the sentences’ from
last lesson?
This is to be FINISHED
FOR HOMEWORK. Due
next Friday 16th
September.
Today’s lesson
• Plotting magnetic fields
• Electromagnetic induction
Plotting magnetic fields
Can you gather
around Mr
Porter?
Quietly and
sensibly
Plotting magnetic fields
Magnetic field lines
The arrows show the direction a compass
needle would point at that point in the field.
The closer the field lines
are, the stronger the
magnetic force felt
Field around a bar magnet
Electromagnetic induction
• Can you carefully wind your wire around
the cardboard tube?
Electromagnetic induction
• Put your coil in this circuit. The multimeter
should be on the μA scale.
μA
Electromagnetic induction
• MOVE a magnet in and out of the coil.
Watch the meter!
μA
Electromagnetic induction
If a magnet is
moved inside a
coil an electric
current is
induced
(produced)
Electromagnetic induction
If a magnet is
moved inside a
coil an electric
current is
induced
(produced)
COPY this please!
Electromagnetic induction
A electric current is induced because the
magnetic field around the coil is changing
(the coil ‘cuts through’ the lines of field).
COPY this please!
Gather round
• http://phet.colorado.edu/sims/faraday/gene
rator_en.jnlp
Can you stick this in please?
Generator/dynamo
A generator works
by rotating a coil in
a magnetic field (or
rotating a magnet in
a coil). A slip-ring
commutator
produces
alternating current
(a.c.)
COPY this please!
Let’s try some questions!
Pages 215 and 219.