Electricity 8 Flashcards
Current meaning
The amount of charges moving past a point in an electric circuit in one second
Voltage meaning
- The amount of electrical energy supplied to each charge so that it can move around an electric circuit.
- The amount of electrical energy used up by a charge as it moves through a load/resistor.
Series circuit meaning
An electric circuit where all components are connected one after the other so there is only one path for charges to flow around
Parallel circuit meaning
An electric circuit in which components are connected alongside each other so that charges can flow through one or the other component, but not both, to complete the circuit.
Energy efficiency meaning
The proportion of useful energy output from a device compared to the energy input, usually expressed as a percentage
Generator meaning
A device that converts another form of energy into electrical energy
How is current measured?
using an ammeter (amps)
How is voltage measured?
using a voltmeter (volts)
How do you calculate resistance?
R = Voltage ÷ Current
State Ohm’s law
V (voltage) = I (current) x R (resistance)
How does voltage change in different parts of a circuit?
Parallel: Same
Series: Splits
How does current change in different parts of a circuit?
Parallel: Splits
Series: Same
What happens to the current in a series circuit as more energy users are added?
It stays the same
What happens to resistance in a series circuit as more energy users are added?
It increases
What happens to voltage in a parallel circuit as more energy users are added?
The voltage for each user is the same as the voltage supplied
What happens to the current in a parallel circuit as more energy users are added?
The current doubles
What happens to resistance in a parallel circuit as more energy users are added?
It decreases
Why are parallel circuits used in homes?
Because more lights can be added without them dimming
What are energy transfers and transformations in a coal power station during the production of electricity?
Chemical energy from burning coal → thermal energy as it turns water into steam → kinetic from turbine turning → electric
How do you calculate energy efficiency?
(useful energy ÷ total energy) x 100
How do you interpret energy rating labels on electronics?
The more stars there are, the more energy efficient
How is electricity generated using a magnet and coils in a coal power station?
The magnet is in the centre of the power turbine station with a large coil around it. The magnet moves creating a magnetic field which irritates the electrons, causing them to flow and create electricity.
