does light travel faster in water or a solid block and why?
923435
light travels as fast as it always travels, no matter what it shines through. Things block light, but it doesn't slow it down.
288483
Not alot actually. Photons bounce around like crazy. When white light strikes a surface some of it is absorbed by the molecules in it. The rest bounces off. When that light hits your eye you see the light whithout the wavelength the surface absorbed giving you the perception of colour. If all light was stopped by matter it would be pitchblack all around you. \n\nNo surface reflects 100% of the infalling light however. Some is always absorbed by atoms and molecules (that become excited ot more energetic) no mather how reflective the surface or transparent the substance. Water may appear completely transparent but only a few hundred meters beneath the surface of the ocean it is quite dark because the water has absorbed the sunlight.\n\nLight ends when a photon is unable to move. A photon is composed of an electric wave and a magnetic wave. Pure energy that is. The higher the frequency of the photon the less likely it is to be stopped by an atom (atoms are composed mainly of empty space). So gamma rays (the photons with the highest energy) are able to pass through matter. But most photons will be stopped by an atom eventually and when that happens the energy of the atom is taken up by the electron in it. The electron moves into a higher orbit: the atom has become excited. Usually, when the electron moves back into its ordinary orbit, the energy is rereleased as heat (low energy infrared photons). Sometimes the energy is rereleased as a photon of a different colour (frequency). The substance glows.
258719
The speed of light in a vacuum is the same for all colors, and this includes all electromagnetic waves outside the human visible spectrum, such as ultraviolet, microwaves, infrared, gamma rays, x-rays, and so on. \n\nIn materials, however, the speed of light is not only slower than in a vacuum, it's also different for each color.  This is why we have dispersion in transparent materials which is responsible for phenomena like chromatic abberation in lenses, rainbows formed by droplets of rain, and splitting of light into a spectrum by a prism.  If the speed of light was slower in a material than in a vacuum, but the same for all frequencies (colors) of light, we'd have refraction, but no dispersion.   \n\nAnd, while nothing can have a velocity higher than that of light in a vacuum, things can go faster than light in a transparent medium.  This causes the electromagnetic equivalent of a "sonic boom", which is called Cherenkov radiation.  \n\nAs for a light year being a "perfect unit of measure", well, it has a rigorous definition developed from basic units of nature on which everyone can agree.  But, so does the meter, or the second, and almost everything other than the kilogram.  \n\nHowever, if you were to send a beam of light into space, you'd find that depending on the frequency it may travel somewhat less than a standard "light year" in one year's time.  This is because space isn't actually a perfect vacuum, and so it does actually have an index of refraction. For many wavelengths, it will be a full light year distance traveled, but some frequencies will travel slightly slower due to the tiny amount of matter, averaging one hydrogen atom per cubic meter, that is present even in deep space.
1023655
well, it is a little slower in air, but not enought to effect any calculations, but it behaves this way because lightbehaves as both a wave and a particle.  The particle characteristic gets slowed down slightly by the air molecules, but the wave portion keeps chugging through the molecules, because waves need something to travel through.  Check out http://en.wikipedia.org/wiki/Speed_of_light
61379
MitchHellman has the best answer!\n\nBut just cuz....a tachyon (theroetical particle) cannot travel *slower* than light. An effect called phase velocity (wave mechanics) can also travel faster than light, but these things are not real in our normal sense of the word. But these are some things people do discuss which have this property.\n\nOtherwise.......no.\n\nlol
775142
All materials have what is called a "refractive index" which is determined by the speed at which light travels through. This is similar to how the speed of sound varies between materials (hard wood vs air). \n\nThe speed of like that you state, 3*10^8 m/s is the speed of light in a vacuum, and only a vacuum.\n\nThe reason the speed of light varies between materials is how light interacts with the atoms in these materials. You see, the way light travels through materials is by getting absorbed by atoms and re-emitted. The energy of an atom rises temporarily. As the energy falls again, the photon is re-emitted out the atom.\n\nThe amount of time it takes for an atom of a substance to do so determines how fast light travels through that substance. This is because the light is just getting absorbed and emitted to be absorbed by the next atom, in a chain!\n\nThis difference in speed accounts for why materials refract light. Without this property, eye glasses, lenses, etc won't work. It is also why things in the water appear distorted etc.\n\nIn a vacuum, however, we cannot change the speed of light, it is a constant.
642439
I assume that the light enters water through the glass since incidence is less than refracted angle also assuming refrative index of glass as 1.66 and water as 1.33\n\nWhat is the question then ? Also how can light return to where it originates ? That is dependent on the setup.
34154
sound travels at an avg speed of .78999342 mps or 2843.9763 MPH in seawater depending on water temperature salinity and depth of the source/receiver.\n\nlight averages 186,282 mps or 11,176,920 mph\n\nthe other answers AREN'T WRONG but you should have specified through what medium they are traveling. also you need to specify temperature humidity pressure altitude/depth salinity and or a myriad of other factors\n\nLight has a different speed when passing through our atmosphere than it does through space just as sound through air and water or a solid. the more dense the material the faster the sound transmission. oddly the opposite is true for light.\n\nthis question has been asked several times before.  if you do a search for previous questions you will doubtless find MANY other answers for these very questions with more precise speeds through different mediums.
707414
Through any transparent or translucent material medium, like glass or air, it has a lower speed than in a vacuum; the ratio of c to this slower speed is called the refractive index of the medium (the actual speed is not affected, the speed of light is constant, the fact that the light is reflected around inside the glass will make a greater amount of time necessary for it to reach the next point). Changes of gravity, however, warp the space the light has to travel through,
694338
Yes, it does, this is due to refraction, which is the bending of light. Images in water always appears nearer, and thus seems larger! n_n
174384
when light moves from 1 medium to another..say air to water..it changes in its speed...this change in speed leads to a change in the direction of the light.
571899
Lightening always takes the quickest path to ground. Water is conductive so if water is the closest conductive thing to ground from the point of origination then it well conduct electricity down to ground.
77099
it would be called superluminal.\n\nyou can read more about it here - \nhttp://en.wikipedia.org/wiki/Faster_than_light
48482
It is how fast light travels. It varies depending on the medium it is going through. The denser the medium, the slower it travels.\n\nIt is possible for radiation to travel faster than light through a medium, I think it is called Korentkov radiation or something like that.\n\nBut the upper limit, based on Einstein's "C" constant is about 186,000 miles per second or 300 million km per hour
60139
The colored piece of glass will absorb more light which will heat it up quicker.\n\nLight goes right through clear glass. Very little light/energy is absorbed.
1135249
The proof is red-shift.\n\nAs things recede from each other at a high fraction of c (speed of light), the waves stretch out; visible light takes on a higher red content.  The SPEED of light remains the same, but the frequency changes.\n\nConversely, when things approach each other, they blue-shift; the light becomes more blue.
971516
When you light a block of glass, part of the light will be absorbed by the glass.\nIn other words, part of the photons will be absorbed by the glass.\nOther photons will be reflected back by the block of glass, and others will pass through it.\nThe lose of energy of your light ray will be seen as a reduction in the number of photons in the ray, in other words, in a reduction in the ray's INTENSITY. Not as a change in the light's frequency.\n\nHowever, the glass will absorb certain light frequencies better than other. (Each matter has its own "absorption graph").\nBecause of that, if your light ray is not a monochromatic one, it is possible that the ratio between the different light frequencies in the ray will change.