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How is temperature measured? And what is the measurement?
Measured by how hot it is + Joules
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If an objects temperature rises what is it taking in?
Heat energy
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If an objects temperature falls, what is it giving out?
heat energy
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if an object has a very high temperature will the heat energy be lost a)very quickly b)very slowly
a) very quickly
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what does the amount of energy needed to raise the temperature of an object depend on?
the mass of an object, the change in temperature required and the material its made from
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what is needed to melt or boil a substance?
energy (heat energy)
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what is the energy during the melting and boiling of water used for?
it is used to break intermolecular forces
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what is specific latent heat?
the amount of heat required to melt or boil 1kg of a substance
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what does specific latent heat depend on?
the material and the state (solid, liquid or gas)
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materials that allow a lot of energy through them are called ...
...conductors
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materials that allow little amount of energy through are called ...
insulators
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give an example of a good conductor?
metals
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give some examples of insulators
rubber, wood, plastic and glass
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what does double glazing reduce and how does it do this?
double glazing reduces convection and conduction by trapping air between the glass
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what does reflective foil on walls reduce and how does it do this?
it reduces radiation as it reflects heat energy back into the room
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what is a good insulator?
air
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how do you work out payback time in years?
payback time in years = cost of installing insulation / annual saving
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what is a cavity wall?
a cavity wall is made up of an inner and an outer wall separated by a cavity (air)
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how can heat loss in a cavity wall be reduced?
by filling the cavity with foam
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what are the 2 process' used to pass air through a cavity wall?
heat energy assing through wall through CONDUCTION and then being transferred from the wall to the cavity by CONVECTION
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what is energy efficiency?
how good an appliance is at converting input energy into useful out put energy
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what is the useful input energy into a television and what is the useful and wasted energy output?
useful input = electrical energy. useful output = light and sound. wasted output = heat
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what is the equation for efficiency?
efficiency = useful output energy (J) / Total input energy (J) X100
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how can heat enegy be transferred from one place to another?
conduction, convection and radiation
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what is conduction?
transfer of heat energy through a substance from a hotter region to a cooler region
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what do metals have that can mover through a material carrying energy?
free electrons
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what does kinetic energy do?
it vibrates particles to heat them up
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what is convection?
transfer of heat energy from hotter regions to cooler regions by movement of particles
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in what substances is conection used?
gasses and liquids
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in what substance/s is conduction used?
solids
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what happens to the air/liquid particles when a liquid or a gas gets ot?
when the particles get hot they become less dense and rise whereas cool air particles are more dense and drop
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what kind of wave is light?
a transverse wave
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how can you calculate the speed of a wave?
wave speed (m/s) = frequency (Hz) x wavelength (m)
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what is refraction and how does it work?
waves speed up or slow down as they pass through a material, this can acuse the wave to slow downor speed up and to change direction
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what is diffraction?
a wave passing through a gap or an opening
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what happens when the gap is larger than the wave in terms of diffraction?
the wave has a slight difraction and only gets slightly larger
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what happens when the gap is smaller than the wave in terms of diffraction?
the wave will get very large
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what happens to the intensity of the wave when diffracted through a gap the same size as a wave?
the intensity will be reduced making the wave less useful
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how can communication be be transferred?
morse code
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Why is a laser used for communication?
because a laser has a more intense beam and very narrow making it more accurate. light also travels very fast
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what kind of signal is morse code and why?
it is digital as it is an on/off signal
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what do all lasers have?
have the same frequency, in phase with each other and have low divergence
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what is the difference between in phas and out of phase waves in terms of energy?
waves in phase produce more energy. waves out of phase produce less energy
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what are some uses of electromagnetic radiation?
microwaves, mobile phones, and radar
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what are microwaves capable of?
absorb fat and water molecules, can penetrate 1cm into the food, cause burns when absorbed into body tissue, reflected by shiny metal surfaces
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what are infared rays used for in daily life?
for remote controls and cooking (heating) food
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how can microwaves be used for communications?
transmitting information over large distances that in line of sight
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what can be a problem when using microwaves for communications?
when the distance isnt in line of sight the signal can become poor
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what are microwaves thought to cause when using mobile phones?
harmful effects such as ear and brain tumors or changes to DNA
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why are children at more of a risk than adults when using mobile phones in terms of microwaves?
their skulls are thinner therefor the microwaves can get through the skull causing more severe effects of microwaves
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how can microwve signals be lost or affected?
large obstacles (trees mountains etc), poor weather, the curve of the earth and interfrence with other signals
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how can problems be reduced when using microwave signals?
limiting distance between transmitters, positioning masts high or on top of hills
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what is the difference between analogue and digital signals?
analogue signals are always on and digital can be turned on and off
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how are digital signals transmitted?
in on and off signals in short pulses
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in what form do analogue and digital signals suffer from interference?
noise interference
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how can radiation for communication be used?
it can be reflected by the atmosphere
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how can radio stations broadcast at the same time?
they use different frequencies
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what are advantages of wireless communication?
no connection to a phone land line, allows access everywhere
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what are the disadvantages of wireless communication?
aerial needed to pick up signal
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how can satellites be used for global communication?
signal from ground dish to satellite receiver dish, then a return signal is sent to a different receiver dish (which cold be in another country)
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what can be reflected by the ionosphere?
longer wavelength radio waves are reflected off of the ionosphere
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what does DAB stand for?
digital audio broadcasting
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what are the advantages of DAB?
more stations, less interference from other stations
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what are the disadvantages of DAB?
audio is not as good as FM, some areas cannot receive DAB broadcasts
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what do earthquakes produce?
seismic waves
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what are the 2 main types of seismic waves?
p-waves (primary waves) and s-waves (secondary waves)
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what type of waves are p-waves ? what can they travel through?
longitudal waves which travel through solids and liquids
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what type of was are s-waves and what can they travel through?
transverse waves and can travel through solids
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which waves travels more slowly a)Primary b)Secondary
b) Secondary
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what can p-waves travel though in terms of the earth?
solid crust, mantle, liquid outer core and inner core.
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what is the epicentre?
the center of the earthquake
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what are the three factors to global warming?
increased energy use in homes, increased co2 emissions from fossil fuels and deforestation
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what type of waves does the sun produce? what do they include?
electromagnetic waves which include ultraviolet radiation
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how long can you stay out in the sun in England without wearing sunscreen?
20 minutes
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if you wear sunscreen factor 50, how long can you stay in the sun??
50 times the amount of time you can stay in the sun without sunscreen
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why do people with darker skin have less chance of skin cancer?
dark skin absorbs more ultraviolet radiation
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how do scientists who study the ozone layer make sure their data is accurate?
re-do the experiments using new equipment, consider data from other scientists, test their predictions on published data
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Other cards in this set

Card 2

Front

If an objects temperature rises what is it taking in?

Back

Heat energy

Card 3

Front

If an objects temperature falls, what is it giving out?

Back

Preview of the front of card 3

Card 4

Front

if an object has a very high temperature will the heat energy be lost a)very quickly b)very slowly

Back

Preview of the front of card 4

Card 5

Front

what does the amount of energy needed to raise the temperature of an object depend on?

Back

Preview of the front of card 5
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