(1)They are robust, and they don't need much maintenance (2)They don't use fuels and they don't need power cables (3) They don't cause pollution and they don't contribute to global warming. (4)They use a renewable energy resource.
1 of 7
Name a disadvantage of photocells?
> It doesn't produce electricity in the dark or if it is too cloudy.
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What are photocells made of?
A photocell contains 2 pieces of silicon joined to make a p-n junction-The n type silicon has an impurity added to produce an excess of free electrons-The p type silicon has has different impurity added to produce an absence of free electrons
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How does photo cells produce electricity?
> Sunlight contains energy packets called photons > Photons make free electrons move making an electrical current.
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What do output from a photocell depend on?
(1) Light intensity (2) Surface area exposed (3) Distance from the light source
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Describe the radiation the sun produces..
> It produces infrared radiation with very short wave length.
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Explain how passive solar heating works..
>Glass is transparent to the sun's short wavelength radiation >The walls+Floors in a building absorbs this radiation warming up and re radiating infrared radiation>
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Other cards in this set
Card 2
Front
Name a disadvantage of photocells?
Back
> It doesn't produce electricity in the dark or if it is too cloudy.
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