do now! can you read page 212 of your text book?
DESCRIPTION
The Motor Effect When a current is placed in a magnetic field it will experience a force (provided the current is not parallel to the field). This is called the motor effect. Can you copy this sentence into your books please.TRANSCRIPT
Do now!
Can you read page 212 of your text book?
Last lesson
• The motor effect and building a loudspeaker
The Motor Effect
When a current is placed in a magnetic field it will experience a force (provided the current is not parallel to the field). This is called the motor effect.
Can you copy this sentence into your
books please.
The Motor Effect
The direction of the force on a current in a magnetic field is given by Flemming’s left hand rule.
Centre finger = Conventional Current
First finger = Field direction
Thumb = Motion
Building a loudspeaker
These also use the motor effect
Coil in here
magnet
HomeworkPages 210 to 213. Answer the
questions on all pages. Finish for homework due 15th October
Today’s lesson
• How the motor effect can build a motor• Electromagnetic induction
Gather round!
D.C.Motor
Commutator ensures that every half rotation the current
direction reverses in the coilbrushes
D.C.Motor
Electromagnetic induction
• Make a coil using wire. The coil should be wide enough to easily move a magnet inside
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.
Gather round
Again?
Generator/dynamo
A generator works in this way by rotating a coil in a magnetic field (or rotating a magnet in a coil)
Motor = generator
If electric energy enters a motor it is changed into kinetic energy, but if kinetic energy is inputted (the motor is turned) electric energy is produced!
Let’s try some questions!Pages 214 and 215.