Electromagnetic Induction Flashcards
In electromagnetic induction, a user supplies what and to produce what?
A user supplies a magnetic field and motion to produce an electric current.
If a wire is moved up and down between a north and south pole so as to cut the magnetic field lines, what happens?
A current is induced in the wire.
If a wire is moved between a north and south pole but no field lines are cut, what happens?
There is no induced current.
If we reverse the direction of the movement of the wire, what happens?
The direction of the current is reversed.
How can we increase the size of the induced current when we move a wire in a magnetic field?
- Move the wire faster
- Use a stronger magnet
- Loop the wire so that several turns pass through the poles.
How can a current be induced in a stationary wire?
A magnetic field is moved into and out of a coil.
What happens once the magnet inside a coil stops moving?
The current stops.
What happens if we reverse the direction of the motion of the magnet in the coil or the polarity of the magnet?
The direction of the induced current is reversed.
How can we detect a reversal of current?
Using a centre-zero ammeter.
What are the two major applications of electromagnetic induction?
- The a.c. generator
2. The transformer.
How can we induce current using two coils?
Change a current in one of two neighbouring coils wrapped on an iron ring.
When inducing current using two coils, what is each coil connected to?
One coil is connected to a switch and a battery, while the other is connected to a centre-zero ammeter to detect electric current and show its direction.
When the switch is closed in the two coil experiment, what happens?
The current in the primary coil is increased, which induces a momentary current in the secondary coil.
When a steady current flows in the primary coil in the two coil experiment, what happens in the secondary coil?
No current flows through the secondary coil.
As the switch is opened in the two coil experiment, what happens in the primary coil?
There is a momentary current in the primary coil, but this time in the opposite direction (than it was when the switch was closed).
