Define efficiency as: (a) (%) efficiency = (useful energy output) / (total energy input) × 100% (b) (%) efficiency = (useful power output) / (total power input) × 100% and recall and use these equations
Describe how useful energy may be obtained, or electrical power generated, from: (a) chemical energy stored in fossil fuels (b) chemical energy stored in biofuels (c) hydroelectric resources (d) solar radiation (e) nuclear fuel (f) geothermal resources (g) wind (h) tides (i) waves in the sea including references to a boiler, turbine and generator where they are used
Define the kilowatt-hour (kWh) and calculate the cost of using electrical appliances where the energy unit is the kWh