always flows from a higher temperature to a lower temperature
1 of 27
What is temperature?
degree of hotnes on an arbitrary or chosen scale
measurement of the average kinetic energy of particles
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What is a thermogram?
temperature can be represented by colours.
the hottest parts are white/red/yellow
the coldest parts are black/dark blue/purple
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What is the formula for specific heat capacity, an
energy = mass(kg) x shc(J/KGdegC) x temp. change(degC)
or e =mc^t
tells you how much energy in joules you need to raise the temperature of 1kg of the material by 1degC
4 of 27
What is the formula for specific latent heat capac
energy=mass(kg) x specific latent heat (J/KG)
or E=M L
tells you how much energy is needed to boil or melt 1kg of a substance
energy is needed to break the intermolecular forces during change of state
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What is CONDUCTION?
conduction of heat is the process in which vibrating particles *** on extra kinetic energy to neighbouring particles
kinetic energy is transferred between particles, vibrating particles pass on their extra energy to neighbouring particles
metals are good conductors due to their free electrons moving and carrying energy with them
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Give 3 examples of good conductors.
metals
copper
aluminium
iron
silicon
graphite (carbon)
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Give 6 examples of bad conductors.
glass
water
plastics
wood
air
materials containing trapped air
wool
fibreglass
expanded polystyrene
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What is CONVECTION?
convection ccurs when the more energetic particles move from the hotter region to the cooler region, and take their heat energy with them.
when you heat up a liquid or gs, the particles move faster and the fluid is less dense. The warmer, less dense fluis rises above the coolder, denser surroundings
s the arm fluid rises, cooler fluid takes its place.
as this continues, you end up with a circulation (convection currents)
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What is RADIATON?
infrared radiation is an electromagnetic wave, carrying energy and needs no medium to travel through. It is reflected by shiny surfaces and is absorbed by dull and rough surfaces
10 of 27
Why do energy loss occur in houses?
energy flows from the heat source (the house) to the cold surroundings (outside)
11 of 27
Name 6 energy saving measures.
loft insulation
fibreglass
rock wool
mineral wool
double glazing
cavity wall insulation
curtains at windows
reflective foil in/on walls
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What is the formula for efficiency? How can this b
efficiency = useful energy output / total energy input
(x100 for percentage)
this can be shown on a SANKEY DIAGRAM
13 of 27
What is the formula for finding out the payback ti
tells you how cost effective different forms of insulation are.
payback time = installation cost/ fuel save per year.
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What is REFLECTION?
15 of 27
What is REFRACTION?
this involes the change in direction of a wave due to passing from one medium to another (e.g. air to glass)
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What is DIFFRACTION?
whenever waves pass through a gap or move around an obstacle, they spread out
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What is TOTAL INTERNAL REFLECTION?
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What is the CRITICAL ANGLE?
when the refracted light emerges parallel to the block, the light is entering at the critical angle.
19 of 27
Whats special about a laser?
20 of 27
How do CD players read CDs using laser technology?
21 of 27
What is the speed of light?
300,000,000 m/s
or
3 x 10^8 m/s
22 of 27
Describe the electromagnetic spectrum.
23 of 27
Describe the model of a transverse wave.
24 of 27
What is the frequency?
the frequency is the number of complete waves, circles, or oscillations per second
measured in Hertz (Hz)
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What is the formula for the speed of a wave?
wave speed(m/s) = frequency (Hz) x wavelength (m)
or
v = f x lamda
26 of 27
What is the relationship between the size of a rec
'the longer the wavelength the long the ariel needed to pick up the signal.'
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