Latest revision as of 12:18, 16 April 2010

Specification References

6.15 recall that a voltage is induced in a conductor or a coil when it moves through a magnetic field or when a magnetic field changes through it; also recall the factors which affect the size of the induced voltage.
6.16 describe the generation of electricity by the rotation of a magnet within a coil of wire and a coil of wire within a magnetic field; also describe the factors which affect the size of the induced voltage.

recall that field lines flow from the North pole to the South pole.
show students that you don't use a power supply, but when you move a wire up and down between two poles of a magnet, current will be recorded by a miliammeter.

have a short 'brain storm' trying to explain how current appears in the circuit you have just shown them
emphasize the fact that a power supply is NOT used and movements of the wire in between the two poles of the magnet have an important role.
Anytime filed lines are cut, current is recorded by the ammeter
If the wire is kept still in between the two poles of the magnet, no current is recorded, so there should a direct correlation between movements of the wire and recorded current.
Whenever the wire moves, it CUTS the field lines and current is induced. This is Electromagnetic induction.
The current induced due to electromagnetic induction is alternating current (a.c.)

Demonstrate electromagnetic induction using all other demos and encourage students to explain, step by step, how current is induced in each case.
Discuss about the vast usage of electromagnetic induction: dynamos, generators.
Use and discuss the ‘a.c.generator’ worksheet (Science Shared)

students to write about the differences and similarities between the ‘electric motor’ and the ‘a.c. generator

@@ Line 21: / Line 21: @@
 ==Homework==
-* Complete Physics texbook - page 211 Q 1-3, page 213 Q1-3
+* students to write about the differences and similarities between the ‘electric motor’ and the ‘a.c. generator
 =Additional Information=