P2

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  • Created by: robyn16
  • Created on: 17-04-14 16:29
What are photocells?
provide electrical energy
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How do photocells work?
they absorb light energy and transform it into electrical energy
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What kind of current do photocells produce? Explain what it is
Direct current- runs in the same direction at all times
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Are photocells renewable or non renewable?
Renewable
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Give 3 examples of where photocells are used?
Mobile phones, space, lights, phone boxes, masts
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How do photocells transform light into energy?
energy is absorbed by silicon atoms, electrons are knocked out of the silicon atoms, free to flow creating the direct current.
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How would you increase the output from a photocell?
increase the light intensity, surface area and reduce the distance from the light to the photocell
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What is passive solar heating?
radiation from the sun passes through the glass, then absorbed from the surfaces which then heats them up, the longer wavelengths of radiation is reflected by the glass
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How do solar stoves work?
light is reflected from the sun with a curved mirror, focuses light onto one place.
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What are solar stoves used for?
to heat up water into steam
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Name the advantages of wind turbines?
renewable, doesn't produce waste
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Name the disadvantages of wind turbines?
spoil the landscape, the wind has to be high enough, must be built where they are not sheltered, need large area
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Name the two different types of electricity.
Direct current (DC) and alternating current (AC)
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Where can you find DC?
in phones, laptops or mp3 players (anything with a battery)
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Where can you find AC?
in the mains because it smoothly switches from positive to negative values
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What is frequency measured in?
Hertz (Hz)
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What is the dynamo effect?
when a piece of wire is moved between the poles of a magnet, Creates voltage which gives off an electric current- HAS TO BE MOVING
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How can you increase the current in the dynamo effect?
stronger magnets, more coil turns, move the wire faster
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How does a AC generator work?
the coil/wire moves around between two magnets by the magnetic field
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What is a thermal power station?
the electricity is generated by using an energy source to heat water- the fuel can be fossil fuels or biomass
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What is the natiional grid?
it is the mains supply which distributes electricity around all electrical appliances
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What is the greenhousee effect?
electromagnetic waves pass through the atmosphere, some wavelengths are absorbed. The gases within out atmosphere absorb infra red radiation and prevent heat escaping.
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Name the three main greenhouse gases.
water vapour, carbon dioxide and methane
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Name the three step process of the greenhouse effect.
shorter waves lengths pass through the atmosphere, the earth absorbs them (warming it), earth then emits the longer wavelengths radiation, the gaseswithin out atmosphere absorb the longer wavelengths which warms it up.
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Why do scientists believe climate change is man made?
the more energy we produce, the more carbon dioxide we produce, deforestation has led to an increase in it which increases our planet to warm up
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Other cards in this set

Card 2

Front

How do photocells work?

Back

they absorb light energy and transform it into electrical energy

Card 3

Front

What kind of current do photocells produce? Explain what it is

Back

Preview of the front of card 3

Card 4

Front

Are photocells renewable or non renewable?

Back

Preview of the front of card 4

Card 5

Front

Give 3 examples of where photocells are used?

Back

Preview of the front of card 5
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