P3

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  • Created by: Ola182
  • Created on: 18-05-17 14:53
What equation links energy to power and time?
Energy transferred = power x time
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What formula could you use to calculate efficienty of an appliance?
(Energy usefully transferred ÷ total energy supplied) x 100
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Why is a hairdryer not 100% efficient?
Because in all appliances energy is always wasted as heat.
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What does a Sankey diagram show?
The total energy input compared to the useful and wasted output.
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List on way energy could be saved at home, at work and on a national scale.
At home - insulate your house (prevents heat created by radiators escaping). At work - avoid unneccesary photocopying (email instead to save paper). On a national scale - the government encorages people to reourages pe
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What is the difference between a primary and secondary energy source?
Primary energy sources are produced directly from coal or wind power or nuclear fuel whereas secondary energy source need other energy sources to work - electricity needs coal, nuclear fuel or wind etc.
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Is electricity a primary or secondary energy source?
Secondary - it is produced using other energy sources (nuclear, coal or wind etc.).
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Describe the basic features of a thermal power station.
Energy released from fuel (usually by burning in a boiler) and used to generate steam. The steam turns a turbine. A generator converts the movement of the turbine (kinetic energy) into electricity.
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Name two sources of energy that power turbines directly without using steam.
Solar cells generate electric current directly from sunlight. Waves provide an up and down motion when they come into the shore which is used to drive a turbine which then drives a generator.
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List four disadvantages of using fossil fuels as an energy source. Why do we still need to use them?
Carbon dioxide is released contributing to global warming. Sulfur dioxide is released causing acid rain. Coal mining messes up landscapes. Oil spills damage the environment. However they produce a lot of energy relativly cheaply.
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Describe the main features of a nuclear power station.
Energy is released from the nuclear fuel by nuclear fission. The heat energy heats water to make steam. The steam turns a turbine. A generator converts the movement of the turbine (kinetic energy) into electricity.
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List three advantages of using nuclear power.
Nuclear reactions release a lot more energy than chemical reactions (like burning). Nuclear power stations don't produce carbon dioxide when making electricity. Nuclear duel (e.g. uranium) is relatively cheap.
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List three disadvantages of using nuclear power.
Produces radioactive waste which is difficult to dispose of as it emits ionising radiation and stays radioactive for a long time. It needs extra safety precautions. The overall cost is high due to the cost of the power plant and final decommissioning
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What is the difference between irradiation and contamination?
Irradiation is being exposed to radiation without coming into contact with the source. Contamination is picking up radioactive waste through breathing it in, eating or drinking it or getting it on your skin.
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Describe the process of generating hydroelectricity.
Water is stored in reservoir above the turbines using a dam. Gravity cause the water to rush through the turbines. A generator converts the movement of the turbines (kinetic energy) into electricity
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Describe the advantages and disadvantages of using hydroelectricity.
It's fairly reliable except in times of drought. Initial costs are high however there's no fuel and no running costs. Flooding a valley has a big impact on the environment (species lose their habitat, rotting vegetation release carbon dioxide, etc.)
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Why can't we carry on using fossil fuels forever?
They are non-renewable and therefore will run out.
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Why can't we easily replace fossil fuels with renewable energy sources?
Renewable sources struggle to produce the same size of energy output as coal or nuclear power stations
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List 5 things that need to be considered when choosing an energy source for a powerstation.
Running cost, setup cost, waste and air pollution, engineering cost, location.
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Explain why renewable sources aren't necessarily cheap.
Renewable resources need bigger power stations than non-renewables for the same output. The bigger the power station, the more expensive.
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Explain how kinetic energy is transformed into electricity in a generator.
In generators a magnet rotates (due to the turbine) in a coil of wire, as it turns the magnetic field through the coil changes which induces a voltage making a current flow in the coil. Want bigger voltage? Turn the magnet faster, more fuel is used.
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What is the national grid?
The network of pylons and cables that covers the whole of Britain. It takes electricity from powerstations to homes and industry.
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What voltage is the mains supply voltage to our homes?
230 V
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Give an advantage and disadvantage of using wave power.
There's no pollution however wave power could never produce energy on a large scale.
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Give an advantage and disadvantage of using tidal power.
Initial costs are quite high however there are no fuel costs and minimal running costs.
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Give an advantage and disadvantage of using wind power.
They spoil the view and are noisy however there is no permanent damage done to the landscape.
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Give an advantage and disadvantage of using solar power.
In sunny countries it's a very good option however not so much in less sunny places.
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Give an advantage and disadvantage of using biofuels as power.
Biofuels are carbon-neutral (the plants absorbed CO2 when growing so when burnt they just release that CO2). However some forests are cleared to grow biofuels - species lose their habitats.
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Give an advantage and disadvantage of using geothermal power.
There are no environmental problems however it is very costly to drill down several km to the hot rocks.
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Other cards in this set

Card 2

Front

What formula could you use to calculate efficienty of an appliance?

Back

(Energy usefully transferred ÷ total energy supplied) x 100

Card 3

Front

Why is a hairdryer not 100% efficient?

Back

Preview of the front of card 3

Card 4

Front

What does a Sankey diagram show?

Back

Preview of the front of card 4

Card 5

Front

List on way energy could be saved at home, at work and on a national scale.

Back

Preview of the front of card 5
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