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A typical coal-fired power plant burns 300 metric tons of coal every hour to generate 2.7 × 106 MJ of electric energy, 1 metric ton = 1000 kg; 1 metric ton of coal has a volume of 1.5 m3. The heat of combustion of coal is 28 MJ/kg. Assume that all heat is transferred from the fuel to the boiler and that all the work done in spinning the turbine is transformed into electric energy.
a. Suppose the coal is piled up in a 10 m × 10 m room. How tall must the pile be to operate the plant for one day?
b. What is the power plant's efficiency?
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