Ex: Police Lightbars, they’re so bright but use so little of the cars battery. Much less than the classic rotating lights.
In: Technology
Old style lights work by heating up a something so it glows, giving off light. But glowing things will always give off most of their light as infra red, or, if you make it really, really hot, ultra-violet. Visible light makes up a small part of the spectrum of lights, so you can’t make these type of lights efficient.
Efficient lights, like fluorescent, sodium or mercury vapour, metal halide, high intensity discharge or LED, use methods other than just ‘something really hot’, to create only light that is in the visible spectrum. When you look at it this way, even these light sources are not really that efficient – turning less than 50% of the energy they use into light. But this handily beats ‘hot thing’ lights which are 5 to 10% efficient.
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