Induction Flashcards
What is induction ?
When the wire passes through a magnetic field a potential difference is induced
What does a potential difference cause ?
Current to flow
Why when the wire is stationary no electricity is generated ?
Electricity is only generated when the wires cutting magnetic field lines
How can you generate electricity ?
- moving the wire and keeping the magnetic field stationary
* moving the magnetic field and keeping the wire stationary
What are the factors affecting current ?
- to increase the current produced:
- increasing the strength of the magnetic field
- increasing the number of wires being cut eg. Using coils rather than a single wire
- increase the speed of the movement
Equation linking power, current and resistance
Power lent = current2 x resistance
How do transformers work ?
By passing a magnetic field between two coils
What does the primary coil create in a transformer ?
It creates an alternating magnetic field because it is connected to an AC supply
What does the alternating magnetic field create in a transformer
The alternating magnetic field creates a voltage in the secondary coil
What does the alternating magnetic field pass around
The transformers core
Why do transformers not work on DC electrical supplies ?
Because DC does not create a change in magnetic field
What is the equation linking voltage a number of turns in a coil ?
Primary voltage
————— =
Secondary voltage
Number of turns in the secondary coil
Why is electricity transmitted at high potential difference ?
Because this reduces the current in the wire and therefore the amount of power lost
What is the power lost in transmission proportional to ?
- resistance in the transmission wires
* current squared
