P2 revision flashcards continued
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- Created by: Rachel Adams
- Created on: 21-05-13 20:01
advantages of fossil fuels
readily available and concentrated source of energy
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disadvantages of fossil fuels
causes acid rain and increases global warming
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advantages of using biomass as a power source
renewable and carbon neutral
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disadvantages of using biomass as a power source
need lots to replace one oump of coal
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advantages of using nuclear power as power source
doesn't produce CO2 and is cheap
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disadvantages of using nuclear power as power source
power stations are expensive to maintain
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what is electromagnetic induction?
creation of a voltage in awire which is experiencing a change in magnetic field
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what is the dynamo effect?
using electromagnetic induction to transform kinteic energy into electrical energy
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what do generators do? what current do they produce?
rotate a coil in a magnetic field, so produce alternating current
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why is elecricity transformed to high voltage before distribution?
makes it cheaper, it keeps current low so means cables don't lose too much heat to surroundings as keep cooler.
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what piece of equipment changes the voltage level?
step up/down transformer
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why do mains electricity work on AC?
because transformers only work on AC
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Are power stations efficient?
no
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how do you calculate energy supplied?
energy supplied = power (kW) x time (hrs)
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how do you calculate cost?
cost = number of units x price per unit
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what type of electricity is cheaper than normal electricity? what appliance takes advantage of this, and how?
off peak electricity. Storage heaters, heat up at night and release slowly throughout day
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briefly explain the greenhouse effect
earth absorbs short wavelength EM radiation from sun. Warms earths surface and emits some of EM radiation back into space with longer wavelength, cooling us down. Atmospheric gases absorb lots of this radiation, reflecting it back towards earth.
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name the three greenhouse gases
carbon dioxide, methane, water vapour
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what has become an increasing problem with global warming
more extreme weather
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what does nuclear radiation cause?
ionisation
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name the three types of nuclear radiation
alpha, beta, gamma
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how are atoms ionised by radiation?
they gain or lose electrons
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how are POSITIVE ions formed?
when atoms LOSE electrons
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how are NEGATIVE ions formed?
when atoms GAIN electrons
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describe alpha particles, how they are stopped and what uses it has
big and heavy, 2 protons and 2 neutrons, don;t penetrate far into materials, strongly ionising as they bash into lots of atoms and knock electrons off them. paper stops them. Used in smoke detectors
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describe beta particles, how they are stopped and what uses it has
they are elctrons, so, small and fast, peneatrate moderately so moderately ionising. 3mm aluminium. Used in medical tracers
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describe gamma rays, how they are stopped and what uses they have
they are a type of EM radiation, and have no mass or charge. Penetrate a long way into materials, so weakly ionising. 3 cm of lead. Kill cancerous cells and sterilise equipment
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explain way to safely dispose of radioactive waste (high and low level)
high level: seal into glass blocks, in metal canisters and then buried deep underground. Low level can be buried in secure landfill sites
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what do planets do to sunlight, and how do they orbit the sun?
they reflect it, and orbit in ellipses
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list the planets in order from closest to the sun to the furthest away
mercury, venus, earth, mars, jupiter, saturn, uranus, neptune
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what are stars like?
hot and far away and huge, give out lots of light
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how is the solar system held together?
gravitational attraction
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what is the force which causes circular motion?
centriPETAL force
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what are asteroids?
piles of rubble and rock from when solar system was forming betwen mars and jupiter
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what are meteorites?
asteroids which have crashed down to earth
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what are comets and how do they orbit the sun?
balls of rock, dust and ice and they orbit in elliptical orbits
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where did our moon originate from?
earth collideded with another planet and their cores merged and less dense material was ejected which came together to form the moon
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what evidence proves this theory?
the moon has a lower density than earth and no iron core but made from the same rocks
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definition of a light year
distance light travels through a vacuum in a year
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advantages of using manned spacecraft
think for themselves and do detailed studies of different areas, and can maintain and repair spacecraft
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disadvantages of using manned spacecraft
have to carry food, water and oxygen, can't withstand as extreme conditions, more expensive
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what is light from distant galaxies called?
red shift
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what does red shift tell us?
frequencies of light from distant galaxies are lower than should be and have shifted towards red end of spectrum. Measurements of red shift tell us all distant galaxies are MOVING AWAY FROM US
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what do more distant galaxies have?
greater red shifts, showing they are moving away faster
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what is cosmic background radiaton, and what does it dropping in frequency prove?
microwave radiation from all parts and directions of universe. It proves big bang theory as as the universe expands, the radiation drops in frequency
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explain the big bang theory
all matter in universe started off very small in a small space. Then it exploded and space started expanding. Happened 14 billion years ago. Expansion still happening
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Other cards in this set
Card 2
Front
disadvantages of fossil fuels
Back
causes acid rain and increases global warming
Card 3
Front
advantages of using biomass as a power source
Back
Card 4
Front
disadvantages of using biomass as a power source
Back
Card 5
Front
advantages of using nuclear power as power source
Back
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