(P2)Electromagnetic Induction Flashcards
How do you induce a current in a wire? (Electromagnetic induction)
If you move a loop of wire into a magnetic field, an induced electric current will flow into the wire
How do you change the direction or increase the current in an electromagnetic induction?
Change direction of motion of the wire, change direction of magnetic field.
Move wire faster, use more loops of wire, use stronger magnets.
Why do generators in power stations usually use electromagnets instead of permanent magnets?
Because they have a stronger magnetic field, to increase the size of the current
Besides increasing the magnetic field, how else can you increase the size of a current in a generator
By increasing the number of turns of the wire and the iron core
What is the main difference between a microphone and a loudspeaker?
(P.S REVISE HOW THEY WORK)
The microphone converts sound waves into electrical signal, the speaker converts electrical signal into sound waves
What are transformers used for?
To change the potential difference of an alternating electricity supply
How does a transformer work?
When an alternating current flows through the primary coil it produces a changing magnetic field in the iron core. This induces an alternating potential difference across the secondary coil, leading to an alternating current when the circuit is produced.
What is the national grid?
A system of wires that transit electricity from power stations to its consumers
What fuels do we use to generate electricity in power stations?
Fossil fuels and nuclear fuels
What does a step up transformer do in the national grid?
It increase the voltage to 132kV or more, which also reduces the current. This reduces energy losses as heat in the wires
What do step down transformers do in the national grid?
Decrease the voltage (increasing the current) for safer use in homes
