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36 Cards in this Set
- Front
- Back
infared radiation
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all objects emit it, makes us feel warm, can travel through a vacuum, (energy from the sun through space) it is a transfer of electromagnetic waves
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surfaces
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dark, matt surfaces: good absorbers and emiiters of infared radiation
shiny, light surfaces: good reflectors of infared radiation |
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conduction
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If one end of a solid is heated, the particles gain kinetic energy and vibrate more passing it on, Free electrons gain the energy as well, colliding with other particles to pass on the energy
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insulators
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contain trapped air
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convection currents
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when the fluid is heated it expands, thus becoming less dense and rises. It is replaced with denser, cooler fluid, this causes the convection currents which transfer energy through the fluid
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Evaporation
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the most energetic molecules escape from the liquids surface into the air thus meaning the average kinetic energy is less so the temp decreases
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what increases evaporation
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-increasing SA
-increasing temperature -creating a draught of air across the liquids aurface |
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rate energy tansferred depends on:
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-material the object is in contact with
-object's shape -objects SA |
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Houses, minimising heat transfer
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-Loft insulation, reduce energy transfer by conduction
-Cavity wall Insulation traps air in small pockets to reduce energy transfer by convection -Double glazing, reduces heat loss by conduction through windows |
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Continued housong energy loss
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-Draught proofing reducing energy transfer by convection
-Aluminium foil behind radiatios to reflect infared radiation back into the room |
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U-value?
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Tells us how much energy per second passes through jt
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Types of energy
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Light, sound, kinetic, nuclear, electrical, GPE, elastic potential and chemical
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Falling objects
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turn GPE into kinectic
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Conservation of energy
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Total amount of energy is always the same, cant be stopped only transferred
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Sankey diagram
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Energy from wind and water
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Wind- to drive turbines
water- falling water, HEP or waves and tides |
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Power from the sun
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Solar energy is transferred into electrical energy by a solar cell
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Geothermal energy
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National grid
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Uses step-up and step-down transformers because they reduce energy wasted in cables, more efficient
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nature of waves
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Transverse: Oscillatiom of the particles is perpendicular to the direction of the wave
Longitudinal: Oscillation of the particles is parallel to the direction of the wave, has compressions and rarefractions |
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types of waves
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-Electromagnetic waves can travel through a vacuum E.G. light or radio
waves which are transverse -Mechanical waves travel through medium substances (can be both types e.g. waves on a spring) -Sound waves are both |
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Measuring waves
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also frequency is number of compressions per second
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Law of reflection
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Image formation by a mirror
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the image in a planr mirror is
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-same size
-upright -same distance between mirror -virtual |
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refraction of light
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refraction continued
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When light enters a:
-more dense substance like glass it slows down and the ray bends towards the normal -less dense substance like air it speeds up and the ray bends towards the normal |
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different colour rays
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refract differently due to different wavelengths, violet light refracts the most and red light the least
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waves
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electromagnetic spectrum
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light
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-white light contains all the colours of the spectrum
-visible light, infared radiation, radio and microwaves all used for communication ROYGBIV |
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optical fibres
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very thin fibres used to transmit signals by light and infared radiation
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Doppler effect
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an increase in the frequency of wave e.g. sound as the observer moves towards the source then vice versa away from the source
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Red-Shift
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galaxies moving away from us give off light that bends towards the red end of the spectrum, every galaxy is moving away thus meaning the universe is expanding
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Blue-shift
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indicates a galaxy is moving towards us. We observe this by seeing dark lines in the spectra from the galaxies
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Big bang proof
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scientists discovered microwaves coming from every direction in soace, cosmic microwave background radiation prpduced by the Big Bang (the only thing proving CMBR)
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