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what kind of energy does the sun emit to earth?
light and heat
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energy from the sun is known as ...?
renewable energy
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what do photocells do? and what do they use to do this?
capture light energy from the sun and they use a flat silicone surface.
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an electric current that always flows the same way is known as...?
a direct current
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what does the power output of a photocell depend on?
the surface area exposed to sunlight
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what is the item called when lots of photocells are joined together?
a solar panel
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what is passive solar heating and where is it usually found?
passive solar heating is when the suns heat can heat up windows that face the sun and is usually found in large buildings.
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the suns energy produces wind, what is this also called?
A convection current
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what are the advantages and disadvantages of wind turbines?
ADVANTAGES-no money after put up, wind is renewable, no chemical pollution. DISADVANTAGES-visual pollution, large amount of space required for the turbines, dependant on wind
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what is the dynamo effect?
the way electricity can be generated by : moving a wire or a coil near a magnet or moving a magnet near a coil or wire.
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how is electricity produced in power stations?
the fuel is burned to release heat energy, heal boils water which produces steam, steam drives the turbines which drives the generators, the generators produce electricity
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a large amount of energy produced produced in power stations is wasted, how?
energy is given off as non-useful energy, this energy is heat is given off
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what is the equation to find the efficiency of power stations?
efficiency = electrical energy output / fuel energy input x 100
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how is the earth sufficiently heated up?
global warming
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the temperature of the earth is rising, what is it called?
global warming
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what do greenhouse gasses include?
carbon dioxide, water vapour, methane
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what are the 2 theories of causes behind global warming?
1. the earth is following its natural cycle 2.mans activity on earth (burning fossil fuels)
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what are the 3 types of fuels commonly used in power stations?
fossil fuels, biomass, nuclear fuel
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what do transformers do in terms of the national grid??
they are used to increase and decrease the voltage before and after transmissions. the voltage is too high for consumers so transformers lower it to make it safe
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why does a wie heat up when being used?
because an electric current causes collisions
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what is economy-7?
when electricity companies offer an off-peak rate for 7 hourse every night as there is less electricity needed during a sleeping period.
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what are the advantages and disadvantages of economy-7?
ADVANTAGES - less demand at night, cheaper for consumer, avoids wasting electricity. DISADVANTAGES - inconvenience to run electricty at night due to noise
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what are the advantages and disadvantages of fossil fuels?
ADVANTAGES - cheap and easy to obtain, doesnt produce SO2, coil-oil are flexible in melting demand. DISADVANTAGES - causes global warming, oil being carried in tankers cause risk of spillage,
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what are the advantages and disadvantages of renewable sources? (e.g- wind, tidal etc)
ADVANTAGES - produces clean electricity, constructed in remote areas, no fuel cost, no chemical pollution. DISADVANTAGES - produce small amounts of electricity, take up lots of space, high initial capital outlay
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what is an electric current?
a flow of electric charge from a battery or other power source to other components in a circuit.
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what can the rate of energy be measured in?
watts, kilowatts, joules
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what is the formula to calculate power?
power = current x voltage
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what is 1 kw in a w?
1kw = 1000w
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how do you calculate the cost of using an appliance for a certain length of time?
total cost (p) = number of kilowatt hours used (kWh) x Cost per unit (p)
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why is nuclear power not a renewable source?
the uranium fuel will run out
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what are some causes of background radiation?
radioactive substances in rocks and living things, cosmic rays from outer space
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what are the three types of radiation?
alpha, beta, gamma
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how can alpha, beta and gamma radiation damage healthy cells?
by ionisation
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what can alpha penetrate?
a few centimetres of paper
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what can beta rays penetrate?
a few millimeters of aluminium
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What can gamma rays penetrate?
many centimeters of lead of a few meters of concrete
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what are the uses of alpha radiation?
they are used in smoke alarms
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what are the uses of beta radiation?
to trace radioactive substances in the ground.
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what are the uses of gamma radiation?
can be used to treat cancer as it destroys the cells and sterilise medical equiptment
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how can you deal with low levels and high levels of radioactive waste?
low level waste is sealed an buried in landfill sites, higher level waste is in glass and underground steel cylinders
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what are the problems with storing radioactive waste underground?
it remain radioactive for a long time, stay away from drinking supplies,
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what is the universe made up of?
planets, comets, stars, galaxies, black holes and meteors
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what are the properties of a black hole?
they have a large mass in a small space
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how are planets and comets kept in their orbits?
gravitational force
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how do planets, comets and satellites stay on the right circular path around the planet/sun?
the larger object (planet/sun) has an inward pull which is provided by gravity, also known as centripetal force
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what are some problems with manned space travel?
planets are far away so can take a long time, fuel required takes up space, must be enough food O2 etc, a stable artificial atmosphere
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what is a more safe and realistic way to travel to the solar system?
unmanned space travel
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probes can be used to send back information about a planets ....
temperature, magnetic field, radiation levels, gravity, atmosphere, surrunding landscape
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how do probes send the information they find out to earth?
radio waves which travel at the seed of light
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what are the advantages to unmanned space travel?
costs are lower due to no food or water needed, safety is no consideration due to no passengers.
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what are the disadvantages for unmanned space travel?
reliability has to be high due to no humans for repair, things on space craft must be zero maintenance
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what are asteroids and where are they normally found?
rocks left over from the formation of the earth and they are normally found in a belt between mars and juipiter
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how do asteroids come towards earth?
they get knocked off of their path and head towards earth
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what are the consequences of an asteroid colliding with earth?
forms a crater, heat could cause fires, sunlight could be blocked out by dust, whole specieis could become extinct
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why cant asteroids join to create a new planet?
Jupiter would have a larger gravitational pull and pull the joined up asteroid which would then break when colliding with Jupiter
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what is a comet made up of?
a small body with a core of frozen gas and dust.
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does the speed of the comet speed up or slow down when nearer the sun and why?
it speeds up. this is because of an increase in strength of gravity
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where do comets come from?
objects that orbit the sun
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what does NEOs stand for?
near earth objects
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what is an NEO?
an asteroid or comet that could possible collide with earth
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how can trajectories be used to to observe an NEO?
it can be observed through a telescope and see the trajectory (path of the NEO)
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what does the theory of the big bang state?
the universe started billions of years ago, the universe is expanding
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what is red shift?
it is the shifting of wavelengths of light towards the red end of the light spectrum
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is it ....... a) the further away the planet the higher the red shift b) the furhter away the planet the less red shift What does this mean?
a, this means the galaxies are moving further faster than the galaxies closer to us.
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how is a pro star formed?
when interstellar gas clouds collapse under a gravitational attraction
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what happens when a pro-star is formed?
thermonuclear fusion happens, releasing lots of energy increasing the stars temperature/
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what happens when a pro star finishes the main sequence?
the hydrogen runs out and the star dies.
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what are the end stages of a heavy weight star?
swells up to form a red supergiant, supergiant rapidy shrinks and explodes, stars under 10x the mass of our stars form a neutron star, stars 10x bigger cause black holes,
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what are the end stages of a medium weight star?
star swells up to form red giant, the red giant shrinks and is surrounded by gas, the core cools and becomes smaller to create a white dwarf
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what does the ptolmaic model of the universe state?
stated the earth was the centre of the universe, and that the earth was surrounded by crystal spheres which held other planets and stars
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what is the copernican model of the universe?
planets sat on spheres, stars were fixed on the outer sphere, the sun is centre of the universe, the earth rotates every 24hrs, takes the earth takes 1 year to revolve around the sun/
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who used a telescope to discover the moon was a perfect sphere and that 4 moons orbited jupiter?
galileo
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Other cards in this set

Card 2

Front

energy from the sun is known as ...?

Back

renewable energy

Card 3

Front

what do photocells do? and what do they use to do this?

Back

Preview of the front of card 3

Card 4

Front

an electric current that always flows the same way is known as...?

Back

Preview of the front of card 4

Card 5

Front

what does the power output of a photocell depend on?

Back

Preview of the front of card 5
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