# physics

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• Created by: eden1
• Created on: 11-05-15 17:06
what does temperature measure?
average kinetic energy of particles
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what is the equation for specific heat capacity?
energy= mass * specific heat capacity * temperature change
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the higher the specific heat capacity....
.... the more energy it takes to increase the the temperature/ more energy is released when it cools
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what is the equation for specific latent heat?
energy= mass * specific latent heat
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the higher the specific latent heat....
.... is a measure of the energy needed to break or form the bonds between the particles to change the state.
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what happens to the temperature when something changes state?
it doesn't change
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what happens to the infra-red radiation with shiny surfaces
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what happens to the infra-red radiation with dark/matte surfaces
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what is conduction?
teh transfer of heat in solids/ transfer of kinetic energy through collisions between particles
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what is convection?
(liquid and gas only) hot air expands, gets less dense, rises, cold air falls and replaces this, this heats up and the cycle continues (hot air that has risen, cools and falls)
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transfer of heat energy through the emissions of infra-red radiation
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what is a good insulator?
trapped air
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what prevents convection currents?
drought proofing
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how to calculate efficiency?
efficiency= useful energy input/ total energy input
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what is the trough of a wave
the lowest parts below the mean
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what is the peak of a wave
the highest parts above the mean
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what is the frequency of the wave
how many wavelengths pass a given point per second
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how do elecrtomagnetic waves travel?
in a straight line
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what is the wave equation?
wave speed= frequency * wavelength
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what is refraction?
the changing of direction of the wave due to change of the optical density between two mediums
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what is diffraction?
this is the spreading out of waves at an opening
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how was light first used in communication
Morse code
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what is total internal reflection?
occurs in an object where it continues to hit the surface of an optical fiber at too shallow an angle for it to refract out and continues to reflect along the fibre
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what are laser beams?
the are coherent (same frequency/ all in phase with eachother and low divergence
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how does infra-red help cook food?
infra-red is absorbed by the surface of the food and increases their kinetic energy. they are reflected by shiny surfaces.
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how do microwaves help cook food?
microwaves are absorbed by water and fat- this leads to a gain in kinetic energy and therefore vibration. this causes heating to occur in the top 1cm of the food.
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which carries more energy (microwaves or infra-red)
infra-red as it has a higher frequency
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how to mobile phones use microwaves?
to send information wirelessly
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how is infra-ref radiation used in TV remotes?
using digital signals in the form of pulses of light
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what is the difference between digital and analogue signals?
analogue signals can have any amplitude whereas, Digital signals are either on or off
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What is an advantage of wireless signals?
thy do not need a wire as they use electromagnetic radiation
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it can be refracted at different layers of the atmosphere and reflected off the upper atmosphere back down to the earths surface.
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what are shorter wavelengths
these can pass through the atmosphere, can be received by a satellite and re-transmitted down to the earth.
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what is a seisometer?
this detects shock waves produced by the earth
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what do earthquakes produce?
S-waves (transverse waves- travel through solids but not liquids and are slower than P-waves), and P-waves (longitudinal waves- travel through both solids and liquids)
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what can exposure to UV radiation cause?
sun tan, sun burn, skin cancer, cataracts and premature skin aging.
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what is SPF
sun protection factor (how many times longer you can be in the sun than without sunblock)
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what do photocells do?
they convert light into electricity in the form of a direct current (DC)- renewable source of energy
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what is DC current?
it travels in one direction only, all the way around in a circuit
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how does the sun cause wind in the form of a current?
the suns lighjt can be absorbed buy the surface and converted into heat which knocks electrons out of the silicone atoms which can now flow freely in a current
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what are the advantages of wind turbines?
they are renewable, and non-polluting
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what are the disadvantages of wind turbines?
they are dependent on wind speed, large and an eyesore
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how can you make a stronger current?
more coils, stronger magnet, faster movement
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what current do generators produce?
alternating current
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what currents do batteries produce?
Direct current
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what are the greenhouse gases
carbon dioxide, methane and water
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what is the greenhouse effect
the blanketing effect of gases in the atmosphere. most wavelengths emitted by the sun can pass through the atmosphere and get absorbed by the surface of the earth which heats up.
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what causes global cooling
volcanic ash
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what do power stations run from?
non- renewable fossil fuels, renewable biomass, and nuclear fuels
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what are the advantages of off peak electricity?
it is cheaper with a lower demand
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what are step up transformers used for?
increase the voltage and reduce the current
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what are the step up transformers used for?
reduce the voltage and increase the current
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radioactive materials give out nuclear radiation over time in the form of what?
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smoke detectors
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in tracers and paper thickness gauges
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treat cancers, in tracers and sterilizing equipment
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what is penetrating power?
how far each radiation can travel into materials
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what does the universe contain?
the universe contains galaxies, which contains stars, around which are planets, comets and meteors
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what is nuclear fusion?
this is where stars emit their own light causing them to be so hot that they emit light in all wavelengths
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how has the moon been created?
it is most probably the remnant of a collision between the earth and another planet.
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what are asteroids?
they are rocks from space left over from the formation of the solar system lying between Jupiter and mars
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what is a NEO?
a near earth object
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what is the big bang theory?
how the universe started in an explosion and is still expanding today. most galaxies are moving away from us with the more distant galaxies moving away quicker.
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what is red shift?
where the wavelength of light emitted by the galaxies becomes longer
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what evidence do we have for the big bang theory?
we detect microwave radiation, the red shift
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what is the life cycle of a smaller star?
small star- red giant- supernova- planetary nebula- white dwarf- black dwarf
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what is the life cycle of a larger star?
large star- red super giant- supernova- neutron star/ black hole
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what is the order of rays?
Radio waves, Microwaves, infra-red waves, visible waves, ultraviolet, x-rays, gamma
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## Other cards in this set

### Card 2

#### Front

what is the equation for specific heat capacity?

#### Back

energy= mass * specific heat capacity * temperature change

### Card 3

#### Front

the higher the specific heat capacity....

### Card 4

#### Front

what is the equation for specific latent heat?

### Card 5

#### Front

the higher the specific latent heat....