Why is UV light harmful, but visible and infrared light are not?

Answer 1

All three are harmful if exposure is excessive, just in different ways. Visible will take out your retinae so that you become blind, IR cooks you like a Thanksgiving turkey and the rest of the electromagnetic spectrum will scramble other circuitry and organs. Try to avoid unnecessary exposure.

Answer 2

The energy of a single packet of light (photon) is proportional to its frequency and inversely proportional to its wavelength. What makes UV light different from visible or infrared is that it has a higher frequency (there are actually things that have even higher frequencies, and are more dangerous: x-rays, gamma rays, etc.). That means that each photon of UV light has a higher energy than visible or infrared.

Now, when light hits an atom or molecule, if it has enough energy, it can actually kick an electron out of that atom. This doesn't seem that big of a deal, but if that atom happens to belong to your body it no longer acts the way it should. It can become what is called a "free radical", which is highly reactive and can go around damaging other atoms in your body.

The body has a natural defense system to fight this, but exposure to UV light can overwhelm our defenses.

Visible and infrared light don't have enough energy to damage atoms in this way, even if you increase their intensity (more photons). They can, however, change molecules in other ways, but that's a story for another question. :)

Answer 3

Hi:

UV ray have a high frequency than light wave . It science way of say they have more energy. Those rays can penetrated the cell membranes and reach into the D.N.A. of the cells and cause mutations. What D.N.A . does it tell the cell machinery how to make proteins but when they are destructed they start make the wrong type of proteins and they are poisons to the cells and eventually they start killing the body . They form tumors as well

they not the only forms of electromagnetic energy to harm the body. X-ray and Cosmic rays can do the same thing however the Earth Magnetic field and atmosphere can filter out the those kind of rays out however some U.V ray and cosmic rays can penetrate the atmosphere . A little U.V. is good because it helps your body make Vitamin D and tan your skin and help plants to ripen their fruits however if you stay out in the sun too long. You, get a sunburn which might mean you will get skin cancer later in life, but the human body does have the ability to recover from such exposures, if you watch how long you stay out in the sun and wear sun screen to prevent further damage to yourself. X-ray from X-ray machine can do the same thing if you are expose to it for a long time. However you are expose for a second or two and there is very sensitive photographic film to get a picture of you body and your expose to less than what you body can handle So it can recover

Hope this explain it

Answer 4

The energy in a photon of light (or any electromagnetic energy) is proportional to it's frequency. UV has a higher frequency than visible light & IR has an even lower frequency. More energetic photons can break chemical bonds creating highly reactive particles called free radicals. It is these radicals that cause the damage.

Answer 5

Hi. The frequency of UV is higher allowing it to penetrate further into the body. Both other types can be harmful if the light intensity is too high.

Answer 6

Who says Visible and IR aren't dangerous to humans? If I thrown enough at you there'll be a lump of carbon where you used to be standing. But to answer your question is going to require a little physics. When photons are incident upon an object those photons can behave in 1 of 3 ways. They can be transmitted, absorbed or reflected. In this case the photons (in the microwave region) are absorbed. And that means that energy is being put into the system. When you put energy into that system the molecules begin to increase their translational and rotational kinetic energy. Put enough energy into the system and you begin to break molecular bonds. Radio is of MUCH lower energy that microwaves. In fact if you took a feather and dropped it from the height of your shoulder it would eclipse all the radio energy ever received from space during modern history.

Answer 7

All light can be harmful even visible if you're exposed to it for a long time.
UV light can hurt you faster because of its high frequency as it penetrates your skin easier and faster.

Answer 8

because even at low intensity, the frequency of UV light is high enough for it to damage your skin and screw up the DNA in your skin (thats how skin cancer forms). this is why its SUPER important to wear sunscreen, especially when youre under really intense amounts of light.

Answer 9

because the iris can't "see" the light so it stays open even when (if visible) the light is strong enough to cause burning.

Answer 10

It burns! The goggles do nothing!