Pick the color with the longest wavelength?

One can hardly believe it, but a human eye sees red only when it looks at light with a wavelength between 620 and 740 nano-meters. Light just past this range is called infrared, or below red, and cannot be seen by human eyes, although it can be sensed as heat.In the language of optics, red is the color evoked by light that stimulates neither the S or the M (short and medium wavelength) cone cells of the retina, combined with a fading stimulation of the L (long-wavelength) cone cells.

What do you think about this phenomenon? Have you ever heard about it before? Please, share your thoughts and experience in the comments below!

More Info: Wikipedia

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39 Comments

Andy Wright

No. Wavelength is a perfectly correct word meaning the length of a wave. I have a degree in physics, worked as a nuclear physicist and now teach it. I have never seen it written as wave length (unless it's a student, and then I am expected to correct it). Absolutely nothing wrong with this question at all

Albeck1994

What's ambiguous about pick the colour with the longest wavelength

Carmine-James Pitaniello

So, you prefer a question like "Where is up", and "Where is down"... I'm sure you couldn't answer that if you were 3.6 light years from Earth. Get a Grip.

Jim Todd

It does.

Jim Todd

Yes, it reads longest wavelength.

John New

Short wavelengths have more energy and danger, longer wavelengths have less energy and are not so dangerous, hence uv rays give us sunburn and xrays and gamma rays get more dangerous.

hazelphyllis

oops wrong again .I always get them back to front

Julia Brandenburg

The photo was a giveaway.

i prashs

Good answer and explanation!

Shish Ahmed

I have an Advanced Level Certificate in Physics from the University of London and have studied this subject in depth for over many number of years. In the spectrum of colors, the color red travels the fastest and hence our eyes observe the color red from a distance before it can see any other color This is the very reason why red is always chosen to represent danger to pre-warn us of dangers that lie ahead, and on the traffic lights to warn us to stop. As this color of light travels the fastest, it has the longest wavelengths ( crest to crest or trough to trough) which is about 700 nano- meters. The shortest wavelength is that of Violet light which has the wavelength of 300 nan- meters. In the wavelengths they are all represented by the Greek letter Lamda.

Maia

Very interesting subject. Haven't learned about this before. Wonder why some people can't see red, and does it have to do with their eye cones and rods?