Mains Electricity

Question 1

What is electricity?

Answer 1

A convenient form of energy that can be generated using different energy resources.

Question 2

What are the 3 fossil fuels?

Answer 2

Coal, oil and natural gas.

Question 3

How were fossil fuels formed?

Answer 3

They were formed from the remains of living organisms millions of years ago and release heat energy when they are burned. They are non-renewable.

Question 4

What are the disadvantages of using fossil fuels?

Answer 4

Fossil fuels are non-renewable; their supply is limited and will eventually run out. Coal and oil release sulphur dioxide gas when they burn, which causes breathing problems for living creatures and contributes to acid rain.
Fossil fuels release carbon dioxide when they burn, which adds to the greenhouse effect and increases global warming. Of the three fossil fuels, for a given amount of energy released, coal produces the most carbon dioxide and natural gas produces the least.

Question 5

What is carbon capture?

Answer 5

Carbon capture and storage is a way to prevent carbon dioxide building up in the atmosphere. It is a rapidly evolving technology that involves separating carbon dioxide from waste gases. The carbon dioxide is then stored underground.

Question 6

What are the two main nuclear fuels?

Answer 6

Uranium and Plutonium.

Question 7

What kind of metals are Uranium and Plutonium?

Answer 7

Radioactive.

Question 8

Why are nuclear fuels burned?

Answer 8

Nuclear fission reactions (where the nuclei in atoms are split) in the fuels release heat energy.

Question 9

What are the advantages of nuclear fuels?

Answer 9

Unlike fossil fuels, nuclear fuels do not produce carbon dioxide or sulphur dioxide.

Question 10

What are the disadvantages of nuclear fuels?

Answer 10

Fossil fuels, nuclear fuels are non-renewable energy resources. If there is an accident, large amounts of radioactive material could be released into the environment. In addition, nuclear waste remains radioactive and is hazardous to health for thousands of years. It must be stored safely.

Question 11

What is wind a result of and what does this mean?

Answer 11

Giant convection currents in the Earth’s atmosphere, which are driven by heat energy from the sun. This means that the kinetic energy in wind is a renewable energy source.

Question 12

What is a wind turbine?

Answer 12

Wind turbines use the wind to drive turbines directly. They have huge blades mounted on a tall tower. The blades are connected to a ‘nacelle’, or housing, which contains gears linked to a generator. As the wind blows, it transfers some of its kinetic energy to the blades, which turn and drive the generator. Several wind turbines may be grouped together in windy locations to form wind farms.

Question 13

What are the advantages of wind energy?

Answer 13

Wind is a renewable energy resource and there are no fuel costs. No harmful polluting gases are produced.

Question 14

What are the disadvantages of wind energy?

Answer 14

Wind farms are noisy and may spoil the view for people living near them. The amount of electricity generated depends on the strength of the wind. If there is no wind, there is no electricity.

Question 15

What is wave energy?

Answer 15

The water in the sea rises and falls because of waves on the surface. Wave machines use the kinetic energy in this movement to drive electricity generators.

Question 16

What is tidal energy?

Answer 16

Huge amounts of water move in and out of river mouths each day because of the tides. A tidal barrage is a barrier built over a river estuary to make use of the kinetic energy in the moving water. The barrage contains electricity generators, which are driven by the water rushing through tubes in the barrage.

Question 17

What is hydroelectric energy?

Answer 17

Like tidal barrages, hydroelectric power (HEP) stations use the kinetic energy in moving water. But the water comes from behind a dam built across a river valley. The water high up behind the dam contains gravitational potential energy. This is transferred to kinetic energy as the water rushes down through tubes inside the dam. The moving water drives electrical generators, which may be built inside the dam.

Question 18

What are the advantages of water power?

Answer 18

Water power in its various forms is a renewable energy resource and there are no fuel costs. No harmful polluting gases are produced. Tidal barrages and hydroelectric power stations are very reliable and can be easily switched on.

Question 19

What are the disadvantages of water power?

Answer 19

It has been difficult to scale up the designs for wave machines to produce large amounts of electricity. Tidal barrages destroy the habitat of estuary species, including wading birds. Hydroelectricity dams flood farmland and push people from their homes. The rotting vegetation underwater releases methane, which is a greenhouse gas.

Question 20

What is geothermal energy?

Answer 20

In volcanic areas, the rocks may heat water so that it rises to the surface naturally as hot water and steam. Here the steam can be used to drive turbines and electricity generators. In some places, the rocks are hot, but no hot water or steam rises to the surface. In this situation, deep wells can be drilled down to the hot rocks and cold water pumped down. The water runs through fractures in the rocks and is heated up. It returns to the surface as hot water and steam, where its energy can be used to drive turbines and electricity generators.

Question 21

What are the advantages of geothermal energy?

Answer 21

Geothermal energy is a renewable energy resource and there are no fuel costs. No harmful polluting gases are produced.

Question 22

What are the disadvantages of geothermal energy?

Answer 22

Most parts of the world do not have suitable areas where geothermal energy can be exploited.

Question 23

How can solar panels and solar cells get confused?

Answer 23

Solar cells convert light energy directly into electrical energy. Solar panels use heat energy from the sun to heat water.

Question 24

What are the advantages of solar energy?

Answer 24

Solar energy is a renewable energy resource and there are no fuel costs. No harmful polluting gases are produced. Solar cells provide electricity in remote locations, such as roadside signs.

Question 25

What are the disadvantages of solar energy?

Answer 25

Solar cells are expensive and inefficient, so the cost of their electricity is high. Solar cells do not work at night.

Question 26

Which power stations start up the quickest and which take the longest?

Answer 26

1. Gas-fired station (shortest start-up time)
2. Oil-fired station
3. Coal-fired station
4. Nuclear power station (longest start-up time).

Question 27

What is a reliable source of energy?

Answer 27

Something that can provide power whenever it is needed. However, their start-up times vary according to the type of fuel used.

Question 28

What is ‘base load’ electricity?

Answer 28

They are run all the time because they take the longest time to start up. Oil-fired and gas-fired power stations are often used to provide extra electricity at peak times, because they take the least time to start up.

Question 29

What is the problem with nuclear power stations?

Answer 29

The fuel for nuclear power stations is relatively cheap, but the power stations themselves are expensive to build. It is also very expensive to dismantle old nuclear power stations and to store their radioactive waste, which is a dangerous health hazard.

Question 30

What is a transformer and where is it used?

Answer 30

It is used in the National Grid. A transformer is an electrical device that changes the voltage of an alternating current (ac) supply, such as the mains electrical supply.

Question 31

What is transformer that increases voltage?

Answer 31

A step-up transformer.

Question 32

What is a transformer that decreases voltage?

Answer 32

A step-down transformer.

Question 33

Where does electricity form a power station go?

Answer 33

1. Step-up transformers.
2. High voltage transmission lines.
3. Step-down transformers.
4. Consumers, for example homes, factories and shops.