Power is the rate of transfer of energy. The more powerful an appliance, the faster the rate at which hit transfers energy. The power of an appliance is measured in watts (W) or kilowatts (kW). 1 watt is a rate of transfer of energy of 1 joule per second (J/s). 1...
Different forms of energy include light, sound, electrical, elastic, nuclear, magnetic, mechanical (kinetic and potential) and chemical. Chemical energy is stored in fuel, food and batteries. This energy is released when chemical reactions take place (battery, food)....
Non-renewable energy sources Fossil fuels are formed in a process that takes millions of years. Fossils fuels are being used faster than they are being formed. They are called non-renewable energy sources because once they are finished they are none to replace it....
Nuclear fusion Nuclear fusion is the process of forcing two nuclei close enough together so they form a single larger nucleus. It can be brought about by making two light nuclei collide at a very high speed. Energy is released when two light nuclei are fused together....
All energy transfers waste energy. The efficiency of a device is a measure of the amount of energy that is usefully transferred. The energy transfers of a device can be represented using a Sankey diagram. Efficiency can be calculated using the energy or power...