National 4 EE Flashcards
(53 cards)
What are our main sources of energy?
Fossil fuels: coal, oil and gas.
What does FINITE mean when describing fossil fuels?
It means that the fossil fuels will eventually run out and take a long time to form.
What are the main sources of renewable energy?
Solar Wind Waves Tidal Geothermal Hydroelectric Biomass
What are the main sources of non-renewable energy?
Coal Oil Gas Peat Nuclear
What is an advantage of renewable energy sources?
They will never run out because they are renewable.
What is an advantage of non-renewable energy sources?
Produce a lot of energy.
What is a transformer?
A device that can change the size of an ac voltage. It can either increase or decrease the size of a voltage.
Describe the structure of a transformer.
Consists of two seperate coils of wire wound in the same iron core.
What equation describes the relationship between the voltage and the number of turns for the primary and secondary coils of the transformer?
Secondary Voltage/ Primary Voltage= Secondary Number of Turns/ Primary Number of Turns
or Vs/ Vp= Ns/ Np
What equation should be used to calculate efficiency?
Efficiency= Output/ Input (Power or Energy)
What happens to the voltage when a coil wire is moved within a magnetic field?
There is induced voltage when the wire moves up and down between the poles.
What factors affect the size of an induced voltage when a wire is moved within a magnetic field?
Moving the wire faster between the poles of the magnet
Using a stronger magnet
Use more conductor eg. make a few turns of the conductor.
How are electrons arranged in a conductor?
The electrons are free to move throughout the structure.
How are electrons arranged in insulators?
The electrons are tightly bound and cannot move.
What is the electric current in an electrical circuit?
The flow of electrons around a circuit. (the greater the flow, the greater the current)
Describe a series circuit.
When components are connected in line, it is said to be connected in series.
What is the unit of current?
Amperes (A)
What is the current at different points in a series circuit?
The same as the current from the battery.
A1= A2= A3
Describe a parallel circuit.
When components are connected so that there is more than one path for the current, it is said to be connected in parallel.
What is current like in a parallel circuit?
The sum of currents through each component in a parallel circuit, adds up to the current which flows from the supply
A= A1+ A2
What is the voltage in an electrical circuit?
The electrical energy supplied by the battery to make the electrons move around the circuit.
What is the unit of voltage?
Volts (V)
What is voltage like in a series circuit?
The sum of voltages across each component in a series circuit adds up to the supply voltage
V= V1+ V2
What is the voltage at different points in a parallel circuit?
The same as the supply voltage.
V1= V2= V3
