Light bulb efficiencies. Sankey diagrams showing the efficiencies of incandescent and energy-saving light bulbs. The incandescent bulb (top) contains a tungsten filament, which glows when an electric current passes through it. Only 10% of the energy produced is light, the rest is heat. An energy-saving fluorescent bulb (bottom) is composed of phosphor-coated glass tubes filled with inert gas and mercury vapour. Electric current excites the mercury and causes the phosphor to emit light. In the fluorescent bulb, 75% of the electrical energy is converted into light, and 25% into heat. | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library |
Bildgröße: | 4181 px × 4181 px |
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Eigentums-Rechte: | nicht erforderlich |
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