Generation And Transmittion Of Energy

Question 1

What is current

Answer 1

The rate of flow of charge around the circuit

Electrons carry the charge

Question 2

What is voltage

Answer 2

An electrical pressure giving a measure of energy transferred

Question 3

What is a.c

Answer 3

Alternating current
It keeps reversing its direction back and forth
it is shown as a wave on a graph

Question 4

What is d.c

Answer 4

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

Question 5

What is electrical power

Answer 5

The energy transferred per second

Power is measured in watts and the higher the power the more energy transferred per second

Question 6

Power =

Answer 6

Current X voltage

Question 7

How can you calculate the power of a component in a circuit

Answer 7

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

Question 8

What is electromagnetic induction

Answer 8

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

Question 9

What factors affect the size of the indices voltage and current

Answer 9

Strength of the magnet
The area of the coil
The number of turns in the coil
The speed of the movement

Question 10

How do generators work

Answer 10

They generate alternating current by rotating a coil of wire between a fixed magnet
A turbine is required to turn the wire

Question 11

What is a dynamo

Answer 11

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

Question 12

What are non renewable energy sources

Answer 12

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

Question 13

What are the problems with using non renewables

Answer 13

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

Question 14

What happens in a power station

Answer 14

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

Question 15

What are nuclear reactors

Answer 15

Nuclear fission produces the heat to make steam to drive the turbines

Question 16

What are renewable energy sources

Answer 16

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

Question 17

What is hydroelectricity

Answer 17

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

Question 18

What is wave power

Answer 18

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

Question 19

What are tidal barrages

Answer 19

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

Question 20

What is wind power

Answer 20

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

Question 21

What are solar cells

Answer 21

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

Question 22

What is geothermal energy

Answer 22

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

Question 23

What is bio mass

Answer 23

Natural waste that can be burned to produce electricity
The waste is burned in power stations
The production of energy is carbon neutral

Question 24

What factors must be considered when setting up a power station

Answer 24

Set up cost 
Set up time
Running cost
Reliability
Location 
Environmental issues

Question 25

How do set up costs effect the power station

Answer 25

Renewable sources need bigger power stations than non renewables
Nuclear power and hydroelectric dams need lots of saftet precautions to make sure that they’re safe for use

Question 26

How does set up time effect a power station

Answer 26

There will be long discussions and it could take a long time to get permission to build the station
Also bigger power stations take longer to build

Question 27

How does running cost effect a power station

Answer 27

Renewables usually have the lowest running cost because there’s no fuel involved

Question 28

How does reliability effect a power statio.

Answer 28

Non renewables are very reliable but will one day run out

Renewables mainly depend on the weather so they’re not very reliable in the U.K.

Question 29

How does location effect power stations

Answer 29

The power station has to be near the stuff it runs on
Hydroelectric must be on hilly rainy places with floodable valleys
Wind must be in windy places
Oil must be near the coast
Nuclear must be away from people

Question 30

What are the environmental issues with building power stations

Answer 30

Burning fuel creates atmospheric pollution
Visual pollution eg wind turbines
Using up natural resources
Noise pollution
Disruption of wildlife
Danger of explosions in nuclear and hydroelectric

Question 31

What Is the national grid

Answer 31

It takes electrical energy from power stations to where it is needed in homes and industry

Question 32

What do transformers do

Answer 32

They step up the alternating voltage to make sure it’s more efficient in transport then step it back down at the end
They have two coils a primary and secondary
A step up has more coils on the secondary coil and a step down has more coils on the primary coil

Question 33

What is the formula for transformers

Answer 33

Primary voltage = primary turns

Secondary voltage secondary turns

Question 34

What is the problem with high voltages

Answer 34

Power loss is still high even when the voltage is stepped up
The high voltage is a risk to people eg when flying kites
There could be links with leukaemia and living near a power line

Question 35

How can you insulate your house

Answer 35

Loft insulation 
Hot water tank jacket
Cavity walls
Thick curtains
Double glazing 
Draught proofing 
Low energy appliances

Question 36

Cost =

Answer 36

Power (kW) X time (hours) X cost of 1kWh