Q4. The diagram shows how electricity is distributed from power stations to consumers.

(a)

(i) What name is given to the network of cables and transformers that links power stations to consumers? (1 mark)

The National Grid

(ii) What does a step-up transformer do? (1 mark)

It alters the composition of the electrical power by increasing the voltage or potential difference component and decreasing the current component

(iii) Explain why step-up transformers are used in the electricity distribution system. (2 marks)

They are used to reduce the current for energy transportation via the cabes. This reduces energy loss / power loss (from cables) and increases the efficiency (of electrical power distribution) (2 marks maximum)

No mark if you say it stops energy loss - it doesn't it just lowers it. Be careful how you express your ideas, incorrect statements will lose you marks.

(b) Most of the world's electricity is generated in power stations that burn fossil fuels.
State one environmental problem that burning fossil fuels produces. (1 mark)

Any one from:

produces pollutant gases / air pollution / acid rain( carbon dioxide / sulfur dioxide / nitrogen oxides)

produces solid waste / ash / smoke

contributes to global warming / greenhouse effect / carbon emissions

Burning fossil fuels doed not affect the ozone layer and carbon monoxide should not be emitted if they are burnt properly.

Saying 'it produces pollution' is too vague for a mark!

(c) Electricity can be generated using energy from the wind. A company wants to build a new wind farm. Not everyone thinks that this is a good idea.

(i) What arguments could the company give to persuade people that a wind farm is a good idea? (2 marks)

Any two from:

using renewable energy

make non-renewable fuels last longer

non-renewable fuels can be used for other processes

no pollutant gases produced - no mark if you say 'no pollution'

land can still be used for farming

(ii) What reasons may be given by the people who think that wind farms are not a good idea? (2 marks)

Any two from:

cause noise pollution

cause visual pollution (spoils the landscape or creates sunlight flicker)

may interfere with TV / radio / mobile phone signals

need to put in new infrastructure (new roads may be needed )

not reliable (depends on how windy the weather is)

dangerous to birds

lots of concrete needed for the bases or producing cement is environmentally damaging

reduces house prices in the area.

Examiners ignored any references to cost / jobs / number of wind generators required or that they take up a lot of land (as it can still be used for farming etc). Any reference to obstruction of shipping etc. was only credited if there was a very clear reference to 'offshore wind farm'.

(9 Marks Total)