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21 Cards in this Set
- Front
- Back
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What is temperature? |
A measure of how hot something is, measured in oc |
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What is a thermogram? Colours are... |
Image that represents heat, white-yellow-red-purple-blue-black |
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What is happening when something warms/cools |
It is taking in energy/loosing it |
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What does the amount of energy needed to raise the temperature of an object depend on? |
Mass, how much the temperature needs to rise, material |
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What is specific heat capacity, equation |
The energy needed to raise 1kg of a material by 1oc
Energy = Mass x SHC x Temp change |
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Why does the temperature stay the same at melting/boiling/freezing ect |
All the energy is being used to break the itermolecular bonds |
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What is specific latent heat? Equation |
The amount of energy required to melt or boil 1kg of a material
Energy = Mass x SLH |
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What is a conductor? What is an insulator? |
Conductors allow energy to flow through them Insulators are much slower |
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Methods of insulation |
Roof insulation Reflective foil Foam cavity wall Double glazing Draught excluders
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What is efficiency? Equation |
A meauser of how good an appliance is at converting input energy to useful output energy
Efficiency = Useful output x 100 Total input |
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What is a sankey diagram |
Shows how much energy is useful |
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What is a useful insulator when insulating houses? |
Air, because the particles are far apart |
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Convection Conduction Radiation |
Transfer of heat by movement of particles Transfer of heat without the substance moving Hot objects emit IR radiation |
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Em spectrum |
Radiio, Microwaves, IR, Visible, UV, X-rays, Gamma |
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What is reflection? What is Refraction? |
EM waves can be reflected from some surfaces A wave speeds up/slows down as it changes medium, this causes the wave to change direction. |
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What is diffraction, when is maximum diffraction |
As waves pass through a gap the edges spread out When gap is the same length as a wavelength |
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What happens when: When angle of incidence is below the critical angle Above critical angle Same as |
Refracted away from normal TIR Light travels along GLASS-AIR boundry |
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What are optical fibres, what are they used for? |
Send information as light, totally internally reflected |
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How are wireless signals sent? Advantages (3) |
By EM radiation 24hrs, now wires, Portable |
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Advantages/disadvanteges of Light communiction |
Fast, Small signal loss Cant be used wirelessly, doesn't diffract well |
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Advantages/ disadvantages of electrical waves for commuincation |
Sent in wires Signal deteriorates |
