Generation And Transmition Of Energy

Question 1

What is current

Answer 1

The flow of electrons around the circuit

Question 2

What is voltage

Answer 2

Potential difference an electrical pressure giving a measure of the energy transferred

Question 3

What it a.c

Answer 3

Alternating current it reverses its direction back and forth
It would show like a wave on a graph

Question 4

What is direct current

Answer 4

It always flows in the same direction and would be a straight line in a graph

Question 5

What is electrical power

Answer 5

The energy transferred per second

Question 6

Power=

Answer 6

Current x voltage

Question 7

How do you use an ammeter

Answer 7

In series with the circuit

Question 8

How do you use a Voltmeter

Answer 8

In parallel with the component you are testing

Question 9

What is electromagnetic induction

Answer 9

Moving a magnet in or near a coil of wire to create a voltage or current

Question 10

How does electromagnetic induction work

Answer 10

As you move the magnet the magnetic field through the coil changes this induces the voltage which pushes a current through the wire
You could also rotate a magnet in the wire or the wire around the magnet

Question 11

What effects the size of the induced voltage or current

Answer 11

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

Question 12

How do generators work

Answer 12

They have a fixed wire with a magnet rotating around it

This is like a dynamo in a bike

Question 13

What are non renewable energy sources

Answer 13

Coal
Oil
Natural gas
Nuclear fuels

They will run out one day
And they damage the environment

Question 14

What are the problems with using non renewables

Answer 14

They all release co2 when burned
Burning coal and oil releases sulfur dioxide causing acid rain
Coal mining is messy
Nuclear waste is very dangerous
Nuclear power always carries the risk of disaster

Question 15

How do power stations work

Answer 15

The fuel goes in as chemical energy
It is burned in the boiler
The heat energy goes to the turbine making it turn
The kinetic energy makes the generator work
The electrical energy goes to the power grid

Question 16

How do nuclear power stations work

Answer 16

Nuclear fission produces steam to drive the turbines

Question 17

What are the properties of renewable energy

Answer 17

It will never run out

They are unreliable and mostly depend on the weather

Question 18

Describe hydroelectricity

Answer 18

A valley is flooded by a big dam
Rainwater is caught and allowed out through turbines
This turns the turbines and creates the electricity

Question 19

Describe wave power

Answer 19

The waves provide an up and down motion which can power a generator
It can be useful on small islands
But is very unreliable

Question 20

What are tidal barrages

Answer 20

Big dams in river estuaries with turbines in them
As the tide comes in the barrages fill up and then the water can be let out through the turbines
It is reliable but not yet readily available

Question 21

What is wind power

Answer 21

Each turbine has its own generator

They only work when it is windy but there is little pollution

Question 22

Describe solar cells

Answer 22

The electric current comes directly from the sunlight

Question 23

What is geothermal energy

Answer 23

The hot rocks under ground are used to heat the water creating steam instead of burning the fossil fuels
There is a high setup cost

Question 24

What is biomass

Answer 24

NAT

Question 25

What must you consider when setting up a power station

Answer 25

Set up cost (it can be expensive to make them safe) Set up time (gas power stations are quickest) Running cost (renewables have the lowest running cost) Reliability (non renewable are much more reliable until they run out) Location(the power station must be near the stuff it runs on) Environmental issues(if a fuel is involved there will be waste and the recourses are being used up,wildlife habitats are destroyed, hydroelectric could flood)

Question 26

What happens in the national grid

Answer 26

Electrical energy from power stations is taken to homes and industry It allows power to be generated anywhere then taken anywhere It needs a high voltage and high current but with a high current there is lots of heat energy lost So it's cheaper to keep the current low with the voltage high

Question 27

What are transformers

Answer 27

They step up the voltage at the start then back down at the end They have two coils(primary and secondary) joined with an iron core

Question 28

What is a step up transformer

Answer 28

It has more turns on the secondary coil than the primary coil so it increases the voltage

Question 29

What is a step down transformer

Answer 29

It has more turns on the primary coil than the secondary and it reduces the voltage

Question 30

How to work out output voltage from a transformer

Answer 30

``` Primary voltage (input)/secondary voltage(output) = no of turns on primary coil/no of turns on secondary coil Vp/Vs= Np/Ns ```

Question 31

What are the problems with transmitting energy

Answer 31

It isn't very efficient so energy loss is high High voltage is a risk to people Links with Leukaemia and living near high voltage power lines have been suggested

Question 32

Payback time=

Answer 32

Initial cost/ annual saving

Question 33

What is a kilowatt hour

Answer 33

The amount of energy used by a 1kw appliance in one hour

Question 34

Cost =

Answer 34

Power x time x cost of 1kwh

Question 35

What are the 9 types of energy

Answer 35

Electrical (whenever a current flows) Light (sun light bulbs etc) Sound (any noise) Kinetic (anything moving has it) Nuclear (released from only nuclear reactions) Gravitational potential (anything that could fall has it) Elastic potential (stretched springs elastic rubber bands) Chemical (fuels food and batteries have it)

Question 36

What are the forms of stored energy

Answer 36

Chemical Gravitational potential Elastic They are not actively doing anything just waiting for it to happen

Question 37

What is the principle of the conservation of energy

Answer 37

Energy can never be created or destroyed only ever transferred from one for to another