The Nature of Light

by Super User
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To understand the nature of light it does take some study of basic scientific fundamentals so when assessing what is best for your particular situation you are armed with knowledge rather than guesswork. 

We have all heard of the light “spectrum” which is what a rainbow displays so vividly for us. It shows us that the white light we see is in fact a mixture of many colours. The reason the rainbow is coloured is because white light is reflected once it travels through a raindrop and the colours dispersed or spread out as it leaves the drop. Red light as seen from raindrops are at an angle of 42º and blue light is from those at 40º to the line of horizon. All other colours come from drops between these two angles.

So what exists outside the limits of the visible light spectrum?

For this you have to know that light is in fact a form of electromagnetic wave consisting of photons from nuclear reactions on the sun. The human eye can see radiated wavelengths from about 380 to 700 nanometres. A nanometre is one billionth of a metre. Red light for example has a wavelength of 650nm and has a “frequency” of 450 million cycles, this being the number of waves of red light that will pass a given point in one second. Radio waves have much longer wavelengths and from the diagram below you can see the pattern of electrical things arounds us emerge. From radio, television, radar, microwaves on to X-rays, gamma rays from atomic bombs and cosmic rays from space. So light is just a small part of this chain.