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14 Cards in this Set
- Front
- Back
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State that thermal energy may be completely converted to work in a single process, but that continuous conversion of this energy into work requires a cyclical process and the transfer of some energy from the system.
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Thermal energy may be completely converted to work in a single process, but continuous conversion of this energy into work requires a cyclical process and the transfer (loss) of some energy from the system as degraded energy.
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Explain what is meant by degraded energy.
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Energy transferred from a system to the surroundings which is no longer available for use.
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Identify different world energy sources
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Coal; Nonrenewable, emits CO2, 22-33 MJ/kg
Oil; Nonrenewable, emits CO2, 42 MJ/kg Gas; Nonrenewable, emits CO2, 54 MJ/kg Nuclear; Nonrenewable, 90,000,000 MJ/kg Waste; Nonrenewable, emits CO2, 10 MJ/kg Solar; Renewable Wind; Renewable Hydro; Renewable Tidal; Renewable Pumped Storage; n/a Wave; ; Renewable Geothermal; Renewable Biofuels; Can be Renewable, Emits CO2 |
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Define energy density
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Energy liberated or released from burning fuel per unit mass of fuel consumed
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State the proportions of world use of different energy sources
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In 2006:
Coal- 40.2% Nuclear- 15.1% Oil- 6.7% Gas- 19.7% Renewables; Hydro-16.2%, Combustible renewables- 1%, Other- .8% Waste- .3% |
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Outline the historical and geographical reasons for the widespread use of fossil fuels
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As the industrial revolution spread, the rate of energy usage greatly increased and industry tended to develop near to existing deposits of fossil fuels. Once factories were established, people seeking work would tend to migrate towards the cities. In addition, infrastructure was created to allow coal and other fossil fuels to be easily transported as the higher rates of energy usage demanded the use of fuels with a high energy density. This encouraged the growth of industries located near raw materials.
Inventions that are important; MAchines used for textile manufacture, The design and improvement of the steam engine (No longer needing flowing water for energy), The development of iron smelting industries (Production is now cheaper thus, allowing growth in te industries based around the manufacture of steel and iron). |
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State the overall efficiency of power stations fuelled by different fossil fuels
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Typical Efficency Current Max. efficiency
Coal- 35% 42% Natural Gas- 45% 52% Oil- 38% 45% |
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Define albedo
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The fraction of the radiation received by the planet that is reflected straight back into space. The global annual mean value is 0.3 on Earth.
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Define emissivity
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The ratio of power radiated by an object to the power radiated by a black body at the same temperature.
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Identify the main greenhouse gasses and their sources
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Methane (CH4)
A pinciple component of natural gas and product of natural decay-decomposition or fermentation. Livestock and plants produce a significant amount of CH4. Carbon Dioxide (CO2) Combustion relases carbon into the atmosphere; plants remove CO2 from the atmosphere during photosynthesis providing that they're growing. Nitrous Oxide (NOx) Livestock and Industries (e.g. the production of Nylon) are a major source Water (H2O) Naturally occuring, it is the small amounts of water vapor (as opposed to clouds) in the upper atmosphere that have a significant effect. |
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State the Stefan-Boltzmann law and apply it to compare emission rates from different surfaces
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For a black body, the total Power radiated per unit area is proportional to its temperature raised to the fourth power.
*You must know how to derive the equation. |
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Define surface heat capacity Cs
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Energy required to raise the temperature of a unit area of a planet’s surface by one degree. Cs = energy/ temperature change of surface
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State what is meant by the enhanced
greenhouse effect. |
Enhancement of the greenhouse effect due to human activities.
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Define coefficient of volume expansion
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The change in volume of a substance per unit volume for a one degree change in temperature.
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