Induced e.m.f. Flashcards
What simple activities demonstrate an induced e.m.f.?
Move a magnet into or out of a coil: A current is induced in the coil.
Move a coil near a magnet: A current is induced.
Place two coils near each other: Passing current through one coil induces current in the other if the magnetic field is changing.
What affects the magnitude of the induced e.m.f.?
Faster motion of magnet or coil = larger e.m.f.
Stronger magnetic field = larger e.m.f.
More turns in the coil = larger e.m.f.
Larger area swept by the coil = larger e.m.f.
This shows that induced e.m.f. depends on the rate of change of magnetic flux.
How can you predict the direction of induced current?
Use Fleming’s Right-Hand Rule:
Thumb = direction of motion of the conductor
First finger = direction of magnetic field (N to S)
Second finger = direction of induced current
