Download OCR Physics P2 - Wey Valley School

OCR Physics Module P2 LIVING FOR THE FUTURE
P2a Collecting Energy from the Sun
The Sun
Photocells
Photocells – advantages
Photocells – disadvantages
Photocell – energy transfer
Photocell – power
Passive solar heating – glass
Solar reflector
Wind turbines
Wind turbines – advantages
Wind turbines – disadvantages
P2b Generating Electricity
Dynamo effect
Dynamo effect – increased
Generator
AC frequency
Battery
Electricity production – stages
Power station
Efficiency
Energy input/output – equation
Efficiency – equation
Transformers
Power transmission
P2c Fuels for Power
Fossil fuels
Renewable biomass
Nuclear fuel
Uranium
Ionising radiation
Plutonium
Nuclear power – advantages
Nuclear power – disadvantages
Power – unit
Electrical appliances – cost
Electrical appliances – power rating
Unit of electricity
Kilowatt hour
Off-peak electricity – factors
P2d Nuclear Radiations
Ionising nuclear radiation
Alpha (α)
Beta (β)
Gamma (γ)
Penetrating power
Background radiation
Harmful effect
Radioactive waste – disposal
Radioactive waste – problems
P2e Our Magnetic Field
The Earth
Earth’s core
Magnets
Cosmic rays
Moving charged particles
The Moon – origin
The Sun
Solar flares
Solar flares – affects
Artificial satellites
stable source of energy; transfers energy to Earth as light and heat
transfer light into electricity; produce direct current (DC); can operate in remote locations; have a power that
depends on the surface area exposed to sunlight
low maintenance; no need for power cables; no need for fuel; long life; rugged; renewable energy resource;
no polluting waste
no power at night or bad weather
energy absorbed by photocell; electrons are knocked loose from the silicon crystal; electrons flow freely
depends on: light intensity; surface area exposed
glass is transparent to light; heated surfaces emit infrared; glass reflects infrared
light reflected to a focus by a curved mirror; efficient solar collectors track Sun’s position in the sky
transfer KE of air to electricity in wind turbines
renewable; rugged; no polluting waste
visual/noise pollution; depends on wind speed; needs space
electricity can be generated by moving a coil near a magnet or moving a magnet near a coil
to increase current; stronger magnets; more turns; faster movement
alternating current (AC); coil of wire; magnetic field; coil and field close; relative motion between coil and field
frequency of AC electricity is the number of cycles per second (Hertz, Hz); UK mains is 50Hz
produces direct current (DC)
source of energy; power station produces electricity; national grid (power lines connect station to consumers);
consumers are homes, factories, offices and farms
burning fuel; producing steam; spinning a turbine; turbine turns generator; significant energy waste
some of the energy of the fuel in a power station is wasted as heat energy in the environmental
fuel energy input = waste energy output + electrical energy output
efficiency = electrical energy output ÷ fuel energy input
increase or decrease voltage; electricity is transmitted at high voltage to reduce energy waste and costs
increased voltage reduces current, so decreasing energy waste by reducing heating of cables
crude oil, coal, natural gas (methane); burning fuels releases energy as heat
wood, straw, manure; biomass fermented to generate methane.
uranium fuel rods release energy as heat; radioactive waste: can be harmful; does not give rise to global warming
non-renewable
from radioactive waste can cause cancer
waste product from nuclear reactors; can be used to make nuclear bombs
independence from fossil fuels; high stocks of fuel; no greenhouse gases
decommissioning costs; pollution from fuel processing; risk of accidental emission of radioactive material;
high maintenance costs
watt (W); kilowatt (kW)
power rating in watts and kilowatts; the length of time it is switched on
power (W) = voltage × current
unit of electrical energy supplied is the kilowatt hour (kWh);
energy supplied = power x time
cost savings, convenience
radiation knocks electrons off atoms (makes positive ions); electrons gained by atoms (makes negative ions)
helium nucleus; used for smoke detectors
electrons; used for tracers and paper thickness gauges
very high frequency em radiation; used for treating cancer, non-destructive testing and sterilising equipment
α stopped by paper; β stopped by thin aluminium; γ stopped by thick lead/concrete
in the environment which is always present; from the Earth (air/rocks etc); Space (cosmic rays); human activity
(nuclear explosions/accidents)
radioactive materials give out nuclear radiation; damages living cells; cause cancers
low level waste in land-fill sites; encased in glass and left underground; reprocessed
radioactive for a long time; terrorist risk; must be kept out of groundwater; acceptable radioactivity level may
change over time
has magnetic field; shaped like bar magnet field; charged particles are deflected by magnetic fields
contains a lot of molten iron
have north and south pole; plotting compass shows the direction of a magnetic field
ionising radiations from space; fast moving particles create gamma rays when they hit atmosphere;
spiral around the Earth’s magnetic field to the poles; cause the Aurora Borealis
electrical current (moving electrical charges) in a coil creates a magnetic field
may be the remains of a planet which collided with the Earth; planets collide; their iron cores merge (forms the
Earth); less dense material orbits as the Moon
source of ionising radiation; causes solar flares that can interfere with the operation of artificial satellites
clouds of charged particles from the Sun; ejected at high speed; produce strong disturbed magnetic fields
satellite communications; electricity distribution
Telecommunications; weather prediction; spying; (satellite) navigation systems
P2f Exploring our Solar System
The Universe
Stars
Planets
Planet motion
Planets motion – forces
Radio signals
Light-year
Manned spacecraft – problems
Unmanned spacecraft – advantages
Unmanned spacecraft – problems
Unmanned spacecraft – send data
stars and planets; comets and meteors; black holes; large groups of stars called galaxies
seen though they are far away because they are: very hot; give off their own light
Mercury; Venus; Earth; Mars; Jupiter; Saturn; Uranus; Neptune; Pluto
gravitational force determines the motion of planets and satellites
gravity provides the centripetal force for orbital motion
take a long time to travel through the solar system because of he distances
measurement of very large distances; the distance light travels in a year
enough fuel; long time required; effect of low gravity on health; shielding from cosmic rays; maintaining a stable
atmosphere; providing enough food and water; keeping warm
withstand conditions that are lethal to humans; safety; costs
reliability; maintenance
temperature, magnetic field and radiation; gravity, atmosphere and surroundings
P2g Threats to Earth
Asteroids
Asteroids – orbit
Asteroids – result of collision
Asteroids – evidence of collision
Comet
Comet – approaches Sun
Near Earth Object (NEO)
Treat of NEO
rocks; left over from the formation of the Solar System
between Mars and Jupiter; large gravity of Jupiter disrupts the formation of a planet
craters; ejection of hot rocks; widespread fires; sunlight blocked by dust; climate change; species extinction
craters; layers of unusual elements in rocks; sudden changes of fossil numbers between adjacent layers of rock
highly elliptical orbits; made from ice and dust; come from objects orbiting the Sun far beyond the planets
strength of gravity increases; speed increases; brightness increases
asteroid or comet on a possible collision course with Earth; can be seen with telescope
surveys by telescope; monitoring by satellites; deflection by explosions
P2h The Big Bang
Big Bang theory
Galaxies
Big Bang – red-shift
Big Bang – estimates
Stars – life cycle
Medium (Sun–like) star – end
Heavy-weight star – end
Black Hole
origin of Universe; started with an explosion; Universe is still expanding
moving away from us; distant galaxies moving away more quickly; microwave radiation received from all parts of
the universe
light from galaxies shifted to red end of spectrum; the further away galaxies are the greater the red shift
the age and starting point of the Universe
start as interstellar gas cloud; gravitational collapse makes protostar; thermonuclear fusion; long period of normal
life (main sequence); end depends on mass of star
red giant; planetary nebula; white dwarf
red giant; supernova; neutron star or black hole
large mass; large gravity; not even light can escape