PATHWAYS REVISION PHYSICS Flashcards
Name tne 10 forms of energ
Magnetic
Kinetic
Heat (thermal)
Light
Gravitational potential
Chemical
Sound
Elastic
Electric
Nuclear
What is the law of conservation of energy
Energy cannot be created or destroyed only transferred
What is the unit of energy
Joules
What is the formula for calculating efficiency
Efficiency = useful energy/total input energy
What is a fuel
A substance that contains a store of chemical or nuclear energy
What is a finite fuel
A non-renewable fuel that cannot be replaced at the rate that humans are using them (they will eventually run out)
What are disadvantages of coal
Produces pollution
Produces CO2 - contributes to global warming and climate changeW
What are some advantages of coal
Enough left to satisfy what we need for now
Electricity made by burning coal is reliable
What are some disadvantages of oil and gas fuel
Produces pollution
Produces CO2 - contributes to global warming and climate change
What are some advantages of oil and gas fuel
Enough left to satisfy what we need for now
Electricity made by burning coal is reliable
What are some disadvantages of nuclear energy
Produces very dangerous radioactive waste that lasts for thousands of years
What are some advantages of nuclear energy
It does not make CO2 and not not contribute to global warming and climate change
Electricity made by nuclear energy is reliable
Name 5 renewable energy sources
Solar, Wind, water (tidal), geothermal, hydroelectric
As solar
Renewable, cheap, does not pollute, no CO2
Ds of solar
Only works when sunny, not a very concentrated source of energy
As water (tidal)
Renewable, does not pollute, no CO2, UK has lots of sea waves
Ds water (tidal)
Need huge numbers of turbines that take up space in the sea, very challenging engineering to build,A
As wind
Renewable, does not pollute, no CO2, UK has lots of wind
Ds of wind
Only works when windy, turbines need to be turned off if too windy
As geothermal
Cheap, free, does not pollute no CO2
Ds geothermal
only works when there are hot rocks near Earth’s surface,
What is geothermal energy
Hot rock in the ground have cold water pumped down to them, steam forms, is used to heat homes and run electricity power stations
What is tidal (water) energy
Up and down motion of sea waves is used to turn turbines that generate electricity
What is solar energy
Special materials turn sunlight into electricity. Or use sunlight to heat water
As hydroelectric energy
Cheap to run, does not pollute, no CO2
Ds hydroelectric enrgy
Expensive to build, only works where there are mountainous lakes
What is hydroelectric energy
In mountainous places lakes high up - have holes drilled in the bottom (or DAMs!) to allow water out through pipes. The water moves very fast and turns turbines that generate electricity
What is work done measured in
Joules
Formula for calculating work done
Work = Force x distance
What is work done
If you move an object and there is a force acting against you e.g. Friction, then you have done ‘work’
What will happen if you do work on an object?
One of its energy stores will increase
What is the formula that links power energy and time
Power = Energy / Time
What are the units of Power
Watt (joules per second)
Define biofuel
Fuels that are being grown or produced by living things
Examples of biofuel
Grown –>
Suns light energy –>
Harvet –>
Burn –>
Chemical energy store –>
Heat + light –>
Replenish (grow back within human lifetime)
What is an example of plant biofuel used for vehicle fuel
Sugar cane
Describe arrangement of particles in solid
Vibrate around fixed position
Regular arrangement
Held in place by reasonably strong bonds
Describe arrangement of particles in liquid
Randomly arranged
Can move over each other but remain touching
Some weak forces holding particles close
Describe arrangement of particles in gas
Particles move around randomly at high speed
Large gaps between particles
Randomly arranged
Fill space they are in
Little to no forces of attraction between particles
Define density
Mass per unit volume of a substance (mass/volume)
How compact a material is for the space it takes up
Units of density?
gram/cm3 or kg/m3
Apparatus used to measure volume of irregular object
Displacement can
Define conduction
Movement of heat energy from a hotter region through a solid to a colder region
How does conduction occur in non-metals
By particles vibrating and starting their neighbouring particles to vibrate
Describe conduction in metals
2 ways:
1. Same as non-metals (particles vibrate and start neighbours to vibrate
2. Delocalised electrons move between the gaps in between particles to start other particles vibrating
Are.metals good conductors
Yes
What is freezing
State change liquid to solid
What is melting
State change solid to liquid
What is evaporating
State change liquid to gas
What is condensing
State change gas to liquid
What is sublimation
State change solid to gas
What is depostion
State change gas to solid
What states of matter does convection occur in?
Liquids and gases
Explain convection
When you heat region of a gas/liquid
Particles move faster
Spaces between individual particles increases
This causes the density of the region being heated to decrease
Because liquids and gases can flow the warmer and less dense region will rise above denser cooler region
After rising to the top it cools down and sinks causing the cycle to repeat
This is a convection current
Real life example of convection current
Radiators!
Metal radiator gets hot from hot water passing through it
Metal touches air around it and heats it
Hotter air rises and is replaced by cooler air - this also gets heated and rises, and so on
What is a scalar quantity
Has size but not direction
6 examples of scalar quantiites
Mass, length, height, any distance, energy, power
Define vector quantity
Quantity has size and direction, represented by arrows
6 examples of vector quantities
Weight, friction, all forces, displacement, velocity, acceleration,
Formula that links weight, gravitational field strength and mass
Weight = mass x gravitational field strength
Define acceleration
the change in velocity over time
define velocity
the speed of something in a given direction
Equation that links velocity, distance and time
Velocity = distance/time
Formula for acceleration
Change in velocity/time
