About ligth, are all types of light the same when we talk about speed? whats the speed of, Neon, White, laser?

Question

can the speed of light be slow down? is neon light at the same speed of white or solar light?

Answer 1

This goes against the other answers you've been getting, but a research group in the United Kingdom did establish that the speed of light IS dependant on frequency. Take a look for yourself ==>http://www.sciencedaily.com/releases/2001/02/010212075309.htm

Answer 2

Yes, once the light it produced, it travels at the same speed. Neon, fluorescent, or laser light is only different in the way that the light is made, not how it travels.

The speed of light slows down depending on what material it's travelling through. It goes more slowly through glass than through air, for example, which is why glass lenses can bend and focus light beams.

Answer 3

Short answer: all light travels at same speed in a vacuum.

However, in different media, not all travels the same speed. This is the theory behind a prism. A prism breaks down wavelengths based on speed through a media. So, in space it is all the same; in a substance the same cannot be said.

Anika: see above, light can slow down in various media. Actually, Harvard has "stopped" a photon in a substance with massive index of refraction.

Answer 4

All forms of light travel at the same speed when in vacuum.

We can make light slow down by passing it through different materials. Depending on the material, this slowing down can range from the unnoticable to the very appreciable.

Answer 5

easy. Special relativity says that light (and indeed all electromagnetic radiation, of which light is only a part of the spectrum) travels at the same speed, roughly 186,282 miles per second. Light can never slow down, it always stays at the same speed, regardless of the speed of the observer.

Answer 6

In vacuum, the "speed of light" is the famous constant that happens to be the maximum speed allowed according to the Theory of Relativity.

All types of light -- in fact all types of electromagnetic radiations including light, radio waves, lasers... -- travel at the same speed in vacuum.

However, inside a medium (such as air, glass, water...), different frequencies travel at different speeds. That is how we explain refraction. Without this feature, we could not have eyeglasses that correct our vision by "bending" the light as it crosses the faces of the shaped lenses. In fact, our eyes would not work as they would be unable to focus the light.

So, yes, different types of light travel at different speeds in different types of medim. Always slower than the "speed of light in vacuum".

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The speed of visible light (let's call it white light) is found by dividing c (the speed of light in a vacuum) by the "refractive index" of the medium. See a list of indices at:
http://en.wikipedia.org/wiki/List_of_indices_of_refraction

The index, for a particular medium, will change as the frequency changes: that is why different frequencies travel at different speeds inside the same medium. However, I have not yet found a site that gives refractive indez by frequency (but I am sure they exist).

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I have found a site that "explains" the way refraction changes with wavelength. However, it is very mathematical.
http://en.wikipedia.org/wiki/Sellmeier_equation

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Here is what I understand: for a given medium, someone tests the refractive index at various wavelengths, depending what the medium could be used for (i.e., they do not test everything at all wavelengths).

A list of refractive indices is published for that material and collected (I suppose) in tables giving such coefficients for groups of materials.

If you need to know the value for a given frequency or wavelength, you look up this list, find your material, then use the closest values they have for wavelengths (e.g., the closest wavelengths above and below the one you are interested in). You calculate the most probable value to use for your particular frequency, then you build your device and see if it works as planned.

The reason that the calculation appears complicated is that no only the speed changes inside the medium. but also the wavelength of the light. The equations ask you to u se the wavelength "in vacuum" -- i.e., the "true" wavelength of the light before it enters the medium.

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For a simpler approach, try:
http://en.wikipedia.org/wiki/Prism_%28optics%29

Answer 7

YEs, all light travels at the same velocity. Slightly less that 3*10^8 m/s.
The velocity of light does change slightl depending upon the material through which it is propagating. This is called 'index of refraction'.

Doug

Answer 8

all photons travel the same speed

usually slightly lower than the speed of light in a vacume,
in a vacume its

299,792,458 m / s