Generation And Transmittion Of Energy Flashcards
What is current
The rate of flow of charge around the circuit
Electrons carry the charge
What is voltage
An electrical pressure giving a measure of energy transferred
What is a.c
Alternating current
It keeps reversing its direction back and forth
it is shown as a wave on a graph
What is d.c
Direct current always flows in the same direction
the voltage and current are always a constant value
It will show a straight line on a graph
It comes from batteries and solar cells
What is electrical power
The energy transferred per second
Power is measured in watts and the higher the power the more energy transferred per second
Power =
Current X voltage
How can you calculate the power of a component in a circuit
Make a circuit with an ammeter a switch a battery and the test component eg a bulb all in series
Connect a voltmeter in parallel with the component
Turn the switch on and record the values on the ammeter and voltmeter
What is electromagnetic induction
When you induce a voltage by moving a magnetic near a coil of wire
As you move the magnet the magnetic field through the the coil changes which induces a voltage and a current flows in the wire
If you move the magnet into the coil the voltage and current are opposite to if you move it out of the coil
If you reverse the magnets north and south polarity then each end will give the opposite voltage and current
What factors affect the size of the indices voltage and current
Strength of the magnet
The area of the coil
The number of turns in the coil
The speed of the movement
How do generators work
They generate alternating current by rotating a coil of wire between a fixed magnet
A turbine is required to turn the wire
What is a dynamo
A type of generator which is used on bikes to power the lights
The magnet is rotated so as the bike wheel turns the magnet also turns
What are non renewable energy sources
Coal
Oil
Natural gas
Nuclear fuels
They will all one day run out
They do damage to the environment
They provide most of our energy
What are the problems with using non renewables
All fossil fuels release co2 when burned which causes global warming
Burning coal and oil releases sulfur dioxide which causes acid rain
Coal mining is messy for the landscape
Oil spillages can happen
Nuclear power carries the risk of major disaster and nuclear power stations are very expensive
What happens in a power station
The fuel is burned in the boiler as chemical energy and heat energy is passed to the turbine which turns it then kinetic energy turns the wire int he generator and the electrical energy is sent to the national grid
When the turbine cools the steam it is condensed and goes back to the boiler at water to be heated again
What are nuclear reactors
Nuclear fission produces the heat to make steam to drive the turbines
What are renewable energy sources
A source that will never run out
They are less damaging to the environment than non renewable
They don’t provide much energy and can be unreliable
What is hydroelectricity
Flooding a valley by building a big dam
Rain water is caught and allowed out by big turbines
The impact on the environment is bad because it kills habitats
Initial costs are high but the running costs are very low
It has an immediate response to energy needs because of the stored water
What is wave power
Waves provide an up and down motion which can be used to power a generator
It’s quite unreliable because there’s not usually many waves when the wind drops
The waves far away from shore are much more powerful so this could be a better option
It could be useful for small islands but not really on large scales
What are tidal barrages
Big dams built across river estuaries with turbines in them
As the tide comes in it fills up the estuaries Nd the water can be allowed out at a controlled speed through turbines
It is reliable and creates a good amount of energy but can only be used in few places
What is wind power
Each wind turbine has its own generator inside
There’s no pollution
They spoil views and can be noisy
They only work when it’s windy
What are solar cells
Sunlight is used to generate an electrical current
They work in a small scale
It is good in sunny places but only works in the day time
What is geothermal energy
Water is pumped down in pipes and heated by hot rocks under the ground then the heat is piped back up to turn the turbine
It is very cheap and there are no environmental problems but the setup costs are very high and there are very few places this can work
What is bio mass
Natural waste that can be burned to produce electricity
The waste is burned in power stations
The production of energy is carbon neutral
What factors must be considered when setting up a power station
Set up cost Set up time Running cost Reliability Location Environmental issues
