The speed of light increases when it goes from glass to air.?
117333
Because of it's wave-like characteristics.\nSame thing happens to sound.  Travels faster in water than in air.  If you are underwater, and you hear a firecracker go off in the air above you, when that sound is passes to the water, the water molecules being more dense, will transmit it faster.\nNo more energy is added, nor does it pick up energy, but the medium vibrates at a faster frequency with the same amount of energy.\nThe amount of energy a wave has does not correspond to the speed at which it travels.
65772
Light can pass through anything transparent, eg space, air, water, glass etc.  In a vacuum, light travels at 300,000,000 metres per second.  However, when light penetrates e.g. glass, it slows down since it finds it more difficult to travel through it.\nWhen light enters a boundary (e.g. the water's surface) at an angle which is not perpendicular to the surface, refraction - the bending of light - is observed.  One common occurence of this is the fact that a drinking straw looks bent in a glass of water.\n\nRefraction is governed by Snell's law which states that Refractive index = sine angle of incidence/sine angle of refraction.  The Refractive index 'n' is a ratio of the speed of light in a medium when compared to the speed of light in a vacuum. n = c/ c in medium.\nA similar effect is observed when water waves travel from deep to shallow water.  The waves slow down but increase in amplitude (height).
144969
It's something along the lines that mass increases with speed. The closer you get to the speed of light the more mass you achieve, which requires more energy to move you. This increases exponentially, always getting closer to the speed of light, until you are essentially immovable, you can't get any heavier so can't move any faster. I heard this explained in a college class once and probably totally got it wrong, but it's in that vein.
444945
The maximum velocity of light is in air (strictly in vacuum).\n\nThe velocity is less in other medium.\n\nThe change in velocity from medium to medium is refraction.\n\nWhen light enters from medium 1 to medium 2, a potion of light is bounced back into the medium 1 and the remaining passes into medium 2 (Refracted). The bouncing back is reflection.\n\nThe proportion of reflection or refraction depends on the angle the ray makes at the point of incidence on the boundary.\n\nWhen light enters from glass (a medium of less velocity; optically denser medium) into air (a medium of more velocity; optically rarer medium) no portion of light is refracted (do not enter into air) at certain angles of incidences. The whole portion of light is bounced back into glass\n\nThey are TOTALLY AND INTERNALLY reflected.\n\nThere is no change in velocity and therefore total ilnternal reflection is not refraction,
495659
The accurate speed of light is 299,792,458 m/s.
274522
The energy in matter is equal to its mass times the square of the speed of light.
11463
The changes propagate at the speed of light, so I guess the time taken is,\n\nt = r/c where c = speed of light
320898
If something moves the speed of light will it become light, just pure energy? Or do atoms gain more and more mass as they approache the speed of light and eventually begin behaving like black holes?  I think it will be hard to find a "correct" answer to this question ;)
193299
It would take infinite energy to accelerate you and your light fixture to the exact speed of light which would thus be impossible.  However, as you approach the speed of light, at ever greater fuel expenditure, your rocket ship would shrink in the direction of travel and you would become a "pancake" but not be aware of it.  When you turn on your light, the photons emitted straight ahead would travel at the speed of light, c.  Photons always travel at the speed of light in a vacuum.  it is not like shooting bullets ahead from a fighter plane where muzzle velocity is added to the speed of the plane.  Although Einstein's theories of relativity do apply to the plane and bullets as well as photons, the effects are almost undetectable at the very low velocities we ordinarily experience on earth.
1171479
To add to debraj's answer, it may help to realise that light has the property of a particle when we force it to stop moving but the property of a wave when it is moving.\n\nIt isn't entirely accurate, but one way to visualise that is to imagine light as wave moving across a still pond. The wave itself has no mass, it is simply a disturbance in the medium (water). But when a wave strikes a massive object it can impart its momentum to that object and thus effectively increase the object’s mass.\n\nLight is also basically a disturbance in a medium, in this case the medium is space-time. While it is moving a photon has no mass of its own (since it only exists as a disturbance). Its existence and movement can only be known by reference to the base energy state of that particular point in space and the change that the passing photon produces. We know the photon exists because it disturbs the base state of a point in space as it passes through that point.\n\nBut when the disturbance strikes a massive object it disturbs that object. That disturbance changes the energy state of the massive object, and since any increase in energy also causes an increase ein mass the struck object becomes more massive. \n\nSo light behaves as though it has mass when we force it to interact with massive objects because mass and energy are interrelated. A photon has virtual mass under those circumstances because it has energy. But the photon itself never truly had mass, it only gained massive properties at the point that it ceased to exist as photon, ie after it collided with a massive object.\n\n(Caveat: that explanation is almost entirely untrue. But all verbal descriptions of quantum and relativistic effects are almost entirely untrue. However it is a very good lie and for the point you are at. Once you understand that lie you can then move onto the next stage, which really does demand mathematical descriptions.)
4925
you either need more information, or this is a trivial problem. \n\ni am assuming the two surfaces of the glass are parallel to each other, so it's not a prism or lens, but a thin flat plate.\n\ntreating it very simply, you could argue that energy is conserved, so the irradiance (which is energy per second per square meter) must be conserved.  the speed of light is fixed in air, so the "per second" part is fixed too.  if the glass surfaces are not angled with respect to each other, then the light leaves the glass taking up the same area that it went in with.  this means the irradiances are the same.\n\nthis is a simplistic physical model, though.  realistically, you will get some reflection at the air-glass interface, reflection at the glass-air interface, and some absorption (both in the air and in the glass).  you need a lot more details about the problem to say anything meaningful though.
588349
The speed of light is invariant---no matter how fast or slow its source is moving, the speed of light remains unchanged (...please don't ask 'why?' because nobody has the vaguest idea) If you're in spaceship going at 99% the speed of light and shine a light outward in any direction, that light will move away from you at the speed of light, no faster, no slower.\n\nWith regards to the answer given that mentions the Doppler effect. The FREQUENCY (wavelength) of light is affected by the speed of the light source (Doppler effect), but frequency has nothing to do with the actual velocity of the light itself.
26330
There is an ambiguity in the question!\nIt is not told in which medium it is.\nThe speed of light is 299,792,458 in vaccum & it is almost the same in air.
981312
310 times faster\n\nif A is going 10mph, and B is going 5mph, the 10/5=2 or twice as fast. so 9.3X10^10 / 3.0X10^8 = 310 times faster.\n\nbut nothing can't go faster than 3X10^8m/s!!!! The normal speed of light means it's going though a vacum (nothing), so if it's going though a gas, it will slow down!! Not speed up! Since the energy will hit atoms and slow down. \n\nIf an object is going 3E8 (short way of 3X10^8m/s) releative to the ground and an object passes it at 3E8, then the object passing the first objects speed was 3E8 releative to the ground... so both were going the same speed, even if some was twice as fast as it!
865196
simple it is because of refraction .\nas glass slab is more denser the speed of light is less \nas it comes out of glass into air (less denser than glass)speed increases
988641
Awesome question.  I have no idea.  The first thing you would have to know is what the properites of glass are that could, if at all, slow the speed of light.  As well as at what thickness of glass, which, in a backwards loop hole sortof way, directly relates to my last sentance.  (if a piece of glass were doubly thick as a single piece of glass, would it cut the speed of light in half?--depends on how thick the original piece was and if the original piece did anything to slow light's speed at all--see where i'm goin?).  Please tell me what you find, I'm very curious, I love questions that make me think deep.  Peace out dude, rioedgebravo@yahoo.com
7206
To be precise, what we usually call the "speed of light" is really the speed of light in a vacuum (the absence of matter). In reality, the speed of light depends on the material that light moves through. Thus, for example, light moves slower in glass than in air, and in both cases the speed is less than in a vacuum. However, the density of matter between the stars is sufficiently low that the actual speed of light through most of interstellar space is essentially the speed it would have through a vacuum, so we don't make much error by ignoring the difference.\n\nTo make it easier for you to convert, here is the speed in alternative units :\n\n(1) 983,571,056.4304461 foot/second\n(2) 11,802,852,677.165352 inch/second\n(3) 1,079,252,848.8 kilometer/hour\n(4) 299,792.458 kilometer/second\n(5) 582,749,918.3585312 knot\n(6) 880,991.0899527 mach\n(7) 670,616,629.3843952 mile/hour (mph)