Why are some wavelengths of EM radiation dangerous, and others not?

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As I understand it, the only real difference between radio, visible light, x-ray and everything in between is its wavelength. For instancew, radio has a very long wavelength, x-ray very short, visible in the middle somewhere. This means that radio can penetrate stuff (matter?) more effectively, among other things.

Radio waves are (essentially?) harmless, but shorter wavelengths are famously more dangerous, from sunburn all the way to straight up cancer and so forth. Why is that?

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Anonymous 0 Comments

The higher the frequency (and shorter the wavelength), the more energy the photons have.

This concept, combined with something called the photoelectric effect, causes biological damage.

The photoelectric effect part is important because the photoelectric effect shows that when photons that are AT LEAST a certain frequency (and no lower) will separate an electron from it’s orbital by exciting it to a free state.

Electrons are the things that ultimately hold molecules together. So, if these electrons go away, the molecules break apart into their component atoms. If the molecules break apart, then the macromolecular assemblies (All of the parts of the cells like the various structures/organelles) fall apart, thus the tissues fall apart, thus the organs fall apart, thus the organism falls apart.

That is why people with very extremely severe radiation poisoning look like they are “melting” to death.

So to be concise, the higher the frequency, then the higher chance it has of causing electrons to become free, thus ultimately causing biological damage.

I think that it is important to note that I oversimplified it and it’s actually the DNA that gets irreversibly damaged to the point that the cell undergoes apoptosis (it kills itself). So, it probably isn’t the radiation that is damaging the cell too badly, it’s actually damaging the DNA. But, that is more cellular biology vice radiology.

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