Flashcards
Physics P3
Flashcards do conjunto (27)
- 1What equation links energy transferred, power and time?Energy transferred = Power x Time
- 2Calculate the cost of using a 5W energy saving bulb for 3 hours if one kWh costs 10p5W = 0.005kW
energy = power x time
energy = 0.005 x 3h = 0.015kWh
cost = 0.015 x 10p = 0.15p - 3What is the power (in kW) of a pair of straighteners using a voltage of 230V and a current of 5A?power = voltage x current
power = 230V x 5A
= 1150W
= 1.15kW - 4Write down a formula you could use to calculate the efficiency of a hairdryerEfficiency =
Energy usefully transferred/Total energy supplies x 100% - 5Why is a hairdryer not 100% efficient?Because some of the energy will be wasted - mainly heat energy as well as sound and light
- 6What does a Sankey diagram show?They are energy transformation diagrams which make it easy to see how much of the input energy is being usually employed compared with how much is being wasted
- 7List one way that energy can be saved at homeStop heat escaping through gaps ceilings windows and around doors by installing loft insulation and cavity wall
- 8List one way that energy can be saved on a national scaleThe government offer grants for better home insulation running schemes to trade in old boilers for new efficient ones and improving public transport
- 9What's the difference between primary and secondary energy sources?A secondary energy source is produced using primary energy sources such as coal, nuclear fuel, wind power
- 10Is electricity a primary or secondary energy source?Secondary
- 11Describe the basic features of a thermal power stationEnergy is released from the fuel
The steam turns a turbine
A generator converts the movement of the turbine (kinetic energy) into electricity - 12Name 2 sources of energy that power turbines directly without the use of steamwind
hydroelectric
wave - 13List 4 disadvantages of using fossil fuels as an energy source. Why do we still need to use them?release Co2 into atmosphere
burning coal and oil releases sulfur dioxide
coal mining makes mess of landscape
oil spillage's cause serious environmental problems
However they produce a lot of energy relatively cheaply and don't rely on the weather - 14Describe the main features of a nuclear power stationEnergy is released from the nuclear fuel by nuclear fission
The heat energy heats water to make steam
The steam turns a turbine
A generator converts the movement of the turbine into electricity - 15List 3 advantages of using nuclear powerNuclear reactions release a lot more energy than chemical reactions
Don't produce Co2 when making electricty
Relatively cheap - 16Explain the difference between irradiation and contamination/
- 17Give an advantage for the following types of power: wave, tidal, wind, solar, biofuels, geothermal/
- 18Give a disadvantage for the following types of power: wave, tidal, wind, solar, biofuels, geothermal/
- 19Describe the process of generating hydroelectricity/
- 20Why can't we carry on using fossil fuels forever?/
- 21Explain why we can't easily replace fossil fuels with renewable energy sources/
- 22List 5 things that need to be considered when choosing an energy source for a power station/
- 23Explain why renewable energy sources aren't necessarily cheap/
- 24Explain how kinetic energy is magically transformed to electricity in a generator/
- 25What is the National Grid?/
- 26What voltage is the mains supply voltage to our homes?/
- 27List 3 disadvantages of using nuclear powerIncreased exposition to ionising radiation increases the damage done to cells
Take the longest time out of power stations to start up
Needs extra safety precautions
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- GCSE My Science (Physics) FlashCards sobre Physics P3, criado por laurenleccles em 26-05-2015.
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- laurenleccles
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