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14 Cards in this Set
- Front
- Back
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The transfer of thermal energy through space from the Sun to the Earth is by: |
1.) Infra Red<?xml:namespace prefix = o />
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Infra-red radiation is absorbed, reflected and emitted to different extents by different surfaces.
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A They are good emitters of infra red radiation |
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Which of the following statements best applies to dark, matt surfaces?
A They are good emitters of infra-red radiation.
B They are good reflectors of infra-red radiation.
C They are poor absorbers of infra-red radiation. D They are poor emitters of infra-red radiation. |
1.) 1-A 2-B 3-C<?xml:namespace prefix = o />
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The diagram shows water being heated in a saucepan on a hotplate.
Match words from the list with the numbers 1 to 4 in the sentences.
A conduction
B convection
C radiation
D insulator
Heat energy is transferred through the base of the saucepan by ……1……
Heat energy is transferred through the water in the saucepan by ……2……
Some energy is transferred from the hotplate to the air by ……3…… The handle of the saucepan is made from wood because wood is a good ……4……. |
1.) A – Draught proofing<?xml:namespace prefix = o />
B – Cavity wall insulation
C – 5 years
D – Conduction
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The diagram shows some ways of reducing energy loss from a house.
The table shows the cost of fitting, and the annual savings on energy bills, for different methods of reducing energy loss from a house.
Method of reducing energy loss Cost of fitting Annual saving Cavity wall insulation £800 £100 Double glazing £4 000 £80 Draught proofing £60 £60 Loft insulation £300 £60
(a) Which method pays for itself in the shortest time?
(b) Which method reduces energy loss by the greatest amount?
(c) The time it takes for the saving on energy bills to equal the cost of installing the insulation is called the pay-back time. What is the pay-back time for loft insulation?
(d) What heat transfer does fitting double glazing reduce?
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1.) To absorb more infra-red radiation<?xml:namespace prefix = o />
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Solar panels use the suns infra-red radiation to heat water. They are painted black – why?
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1.) Larger surface area to increase heat loss<?xml:namespace prefix = o />
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African Elephants have bigger ears than Indian elephants – why?
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1.) Evaporating molecules are the most energetic, meaning the average energy drops after they have left<?xml:namespace prefix = o />
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Why do liquids cool down as they evaporate?
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Larger surface area, higher temperature, wind |
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What can be done to speed up the rate at which liquids evaporate? |
1.) White is a poor absorber of infra red, making the fridge cooler<?xml:namespace prefix = o />
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Why are fridges almost universally white? |
1.) The freezer – bigger difference in temperature<?xml:namespace prefix = o />
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A fridge freezer is in a room of temperature 20 degrees, the fridge is at 5 degrees and the freezer at -18 degrees. Which will have the faster heat transfer?
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How much energy is required to raise the temperature of 1kg of a material by 1 degree |
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What does specific heat capacity mean?
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1.) 288000J<?xml:namespace prefix = o />
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How much energy is required to raise 2 kilograms of water (c = 7200 J/KgoC) by 20oC? |
1.) Low u-value<?xml:namespace prefix = o />
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When purchasing double glazing would you want windows with a high or a low U-Value? |
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