One tonne of coal, if fully burned, releases 28 Gigajoules (GJ) of thermal energy. However, for each tonne of coal burned in its boiler, a modern electrical power plant produces only 12 GJ of electrical energy.

1. Which law of nature explains the difference?

2. What is the energy conversion efficiency of such a power plant?

3. If the electrical transmission and distribution network between the power plant and your home has an efficiency of 95%, then how much electrical energy is ultimately delivered to customers from that original tonne of coal?

4. What has happened to the energy that did not reach customers?

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1 The second Law of Thermodynamics 2 Efficiency ... View the full answer