Tuesday, 12 March 2013

EM Spectra

What is Light? How are the other EM Spectra different?

They are not is the simple answer. From Gamma rays to radio waves the EM spectra is just the same, its only that we perceive them differently and need different ways of detecting the waves.

Lets look at an example.
We see light in all its different colours. Each different colour is a different wavelength. Lets look at Infra red. if I shine an infra red beam at you, you don't see it simply because your eyes don't detect infrared radiation. If I direct a camera (that has a wider capture range than your eye) at an infrared beam then I can "see" it - simply because the camera detects the light and changes its wavelength into something you can see.
You Tube video of a looking a Sky remote

So know you can see IR light then UV is the same. Moving further along the spectrum then we need different types of detectors to detect the radiation. Our hands work well as detectors on the lower end of the infrared and for more frequencies we need more and different detectors.

The detectors change but the nature of the waves does not change.

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