Flashcards
Physics Unit 1
Flashcards do conjunto (41)
- 1What does conservation of energy mean?Energy cannot be created or destroyed, only transformed or transferred.
- 2Describe the energy transfer that takes place in a microphoneElectrical energy is converted into sound (useful) and heat (waste)
- 3Describe the energy transfer that takes place in a laptopChemical energy is transferred to light (useful), sound (useful) and heat (waste)
- 4A phone charger has an input energy of 5J. It wastes 1.5J as heat. Draw a Sankey diagram to show this energy transfer.
- 5What is the formula for efficiency?Efficiency = Useful output power /
Total input power - 6What is the definition of power?The rate of energy transferred
- 7What is the formula for power?Power (W) = energy (J) / time (s)
- 8What are Kilowatt hours a unit of?Energy
- 9How do you work out kilowatt hours?Kwh = kW X hours
- 10How do you work out GPE?Mass x gravity x height
- 11Why does a pendulum gradually not swing as high?Some energy is lost because it is wasted as sound and heat
- 12What is the formula for energy?Energy = power x time
- 13How do you work out payback time?Payback time (years) = cost of insulation / saving each year
- 14How do you work out cost effectiveness?Saving each year/cost of insulation
- 15What is a U-value and what does a low U-value tell us?A U-value is a measurement of the rate of heat loss through a material. The lower the U-value, the better the material is as an insulator.
- 16In a power station what happens in the boiler?Burning coal heats water. The water turns to steam and leaves the boiler.
- 17In a power station what happens in the turbine?Steam turns the turbines. The steam then leaves the turbines and is cooled in huge towers and the water can be recycled.
- 18In a power station what happens in the generator?The turbines drive a large magnet inside a coil. Moving the magnet generates electricity.
- 19In a power station what happens in the transformer?The transformer changes the voltage from 25,000V to 400,000V
- 20What is a fuel?A source of energy
- 21What is oil?Fossils of animals
- 22What is coal?Fossils of plants
- 23What are some advantages of wind power?Clean
Renewable source of energy - 24What are some disadvantages of wind power?Turbines look ugly and are noisy
Unreliable - 25Advantages of water power?Renewable
Doesn't affect coastal views - 26What are some disadvantages of water power?Waves can damage turbines in wave power
Tidal power can only be used in places where there is a 5m difference between high and low tide - 27Describe wave powerWaves force the air up and the trapped air turns the turbine which turns the generator.
As the wave comes down, the air comes back - 28Describe tidal powerA tidal power station traps each high tide behind a barrage and uses it to turn the generator to make electricity.
- 29Describe hydroelectric powerDam. Dam wall is much thicker at the bottom than the top because the pressure of the water increases with depth. Falling water turns the turbine.
- 30Describe geothermal energyGeothermal energy harnesses thermal energy stored within the Earth. Cold water goes down, gets heated up by radioactive rock, the comes back up as steam and turns the turbine.
- 31What causes acid rain?Sulfur dioxide, produced when sulfur is burned. Sulfur occurs due to impurities in fuels.
- 32What does the first step down transformer do?Reduces voltage from 400,000V to 25,000V
- 33What does the second step down transformer do?Reduces voltage from 25,000V to 230/240V
- 34Does a step up transformer have more coils on the output side?Yes
- 35What is the order of start up times for power stations from shortest to longest?Natural gas, oil, coal, nuclear
- 36Energy can be dissipatedTrue
- 37What is a kilowatt hour sometimes called?A unit
- 38Why does voltage need to be increased before electricity goes down power cables?Increasing the voltage reduces the current required and this reduces the heat energy losses form the cables
- 39What is carbon capture?Carbon capture is the capture of the carbon dioxide released by burning fossil fuels
- 40—
- 41Name two radioactive fuelsUranium
Plutonium
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- Studying for GCSE Science (Physics) FlashCards sobre Physics Unit 1, criado por Melissa Quail em 25-06-2014.
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- Melissa Quail
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