light does travels round conners pls explain.?
146069
The tendency of light to travel around corners is called diffraction.It is due to the mass character of light.So light bends around the edges.This can be seen from the fact that when light passes near a planet , it bends towards the planet.This can be tested during solar eclipse.
413107
I will have to answer your question in two parts.\n\nElectrons in a piece of metal move around randomly with speeds of about 10^5 m/s. This is just the thermal velocity associated with the energy the electrons possess without any electric field present.\nWhen an electric field is applied, the electrons acquire a miniscule drift velocity. This velocity is miniscule compared to both the thermal velocity AND the speed of light.\nElectrons flowing as a current have speeds no where near the speed of light, whether you speak about the thermal or drift velocities.\n\nHOWEVER, the SIGNAL DOES travel close to the speed of light. Signal speeds are typically about 2/3 the speed of light. Just do a simple coaxial cable calculation to find a wave equation, and you can find the conduction speed.\nThe reason for this is that the Electric field applied can cause electrons ALL THROUGHOUT the circuit to move, and thus the speed of the signal is greater than the drift speed of the electrons.\n\nThe other answers are wrong in saying that ELECTRONS travel close to the speed of light.\nIt is correct to say that ELECTRICAL SIGNALS travel close to the speed of light, however.
43650
Light travels through space as photons (tiny mass-less packets of energy).  Photons can interact only with the electrons surrounding an atom or molecule by kicking them to higher energy levels in higher orbits or shells.  If there is no matter with electrons (a perfect vacuum) the photons travel on unimpeded at the speed of light.  Space is almost a perfect vacuum and starlight (photons) can travel for thousands of light years without interacting with electrons to reach your eye.
208088
Actually light travels at the same speed no matter how fast it's source is traveling, nor which direction, as long there does not exist a certain level of gravity. Brightness of light however may be relative, except that you will have a definitive amount of photons in a given space...but we have no way of measuring that. The problem with the speed of light, however, is that gravity has an effect on it. Supreme amounts of gravity can actually attract photons and slow them down, or curve their direction towards the object. we do not know whether light actually orbits black holes because it's  constant inertia gives it enough centrifugal force, or if the light is actually sucked right into the object.\n\nYes everything is relative to something else. Your name spelled in English letters is even relative to other spellings of your name. Emotions are relative, hieght is relative, color is relative, even time is relative.\n\nThis is only true if you agree with Einstein's theory of relativity, but you couldn't say you didn't agree with it, because you would have to read all of it to understand. He has math that proves everything as relative, somehow.
188402
You don't need a force to enable something to travel, it's quite the opposite! Remember the Newton's First Law: an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force.\nOf course Newton's Laws doesn't directly apply to light, which is best described by quantum mechanics as a flow of photons. However, I'm referring to it because its rationale holds also for photons and its formulation is very intuitive (opposite to quantum mechanics).\nOnce photons are emitted by a light source (for instance, electrons changing energetic level within an atom), they "just go", with no need of energy other than the energy that produced them in the first place.
600967
No there is no 'summation' of speeds involved with light.  Light is Electro-Magnetic Energy, although light travels as particles as well as waves.  In this Universe the speed of light is a constant, roughly 186,000 miles-per-second, or 300,000 km/sec or 300 Mega-Metres / sec.  Unless some POWERFUL external force acts upon light, it cannot change speed.  This entails the gravity of black-holes and such. (Not even light can escape from them.)\n\nA vehicle might weigh somewhere in the neighbor-hood of 3,300 lbs. (Approximately 1,500 Kg, for those of you who have not learned to count properly, just yet ...)\nCheck out da' math ...\n\n60mph = 100 kmph = 27.77r mps. \n(1,500 Kg x 27.77r mps) / 9.81 mps = ~ 4,246 N\n\nI doubt, very seriously, that a little over 4,000 Newtons is enough force to even put a dent in the factor of light-speed.  For more info, look-up Einstein's Theory of Realtivity' (Although I believe 90% of it to be short-sighted ancient crap ...)  This subject is covered in it ...\n(umm covered in Einstein's Theory, not copvered in crap .. which err .. is the same thing at times ...
330302
Light is a kind of energy that can travel through space. Light from the sun or a light bulb looks white, but it is really a mixture of many colors. The colors in white light are red, orange, yellow, green, blue and violet. You can see these colors when you look at a rainbow in the sky. \n\nThe sky is filled with air. Air is a mixture of tiny gas molecules and small bits of solid stuff, like dust. \n\nAs sunlight goes through the air, it bumps into the molecules and dust. When light hits a gas molecule, it may bounce off in a different direction. Some colors of light, like red and orange, pass straight through the air. But most of the blue light bounces off in all directions. In this way, the blue light gets scattered all around the sky. \n\nWhen you look up, some of this blue light reaches your eyes from all over the sky. Since you see blue light from everywhere overhead, the sky looks blue. \n\nIn space, there is no air. Because there is nothing for the light to bounce off, it just goes straight. None of the light gets scattered, and the "sky" looks dark and black.
64267
Well, if you're traveling faster than light, then the light can never be in front of you.  There would be just a big nothing, probably drive you crazy if you looked at it.  I know, I come from andromeda.  We travel through space backwards so we can see where we're going.
162064
Light does'nt require a medium to travel in. Light can behave like particles as well as waves and waves don't require a medium to travel. For more information refer to http://www.howstuffworks.com/ or http://www.wikipedia.org/
2702
Light has nothing to do with space. It is a property of the electromagnetic field when this field is undergoing changes. from its point of origin, this field radiates out into space in all directions. It is invisible, but can be felt by charged particles. When this field is changed, for instance by suddenly altering the position of its emitter, a kink develops in the field which propagates out into space at the speed of light. Under the right circumstances of acceleration, this kink becomes electromagnetic radiation - light. So space simply acts as a passive container for the electromagnetic field, which in turn is the 'medium' in which light exists.
1028067
Imagine the light wave from a point source like the circular waves produced when you drop a stone in water.  As the wave moves out, each point on the wavefront behaves like its own point-source and the constructive/destructive interference of these "wavelets" cause the wave to continue to propagate.\n\nIn 3-dimensions, the light from the sun is like a spherical wave propagating out. The wavefront is perpendicular to the direction of travel. The sun is about 93 million miles away, so by the time the wavefront reaches the earth, the tangent to the "spherical" wavefront is essentially the same as the wavefront itself. Hence, it can be represented as a plane wave because the spherical nature of the wave becomes insignificant.\n\nHowever, with a "nearby" lamp, the spherical wavefront retains its shape - i.e., we cannot neglect the shape of the wavefront. The effect is similar to placing a ruler tangent to circles of different radii. A ruler placed alongside a circle of 93 million mile radius would be virtually indistinguishable from the circle itself.
321687
OK, to answer this question, we first have to make a few important assumptions, otherwise the question is meaningless.\nFirst, we have to assume that you can accelerate your car to the speed of light....this is not actually possible since it would have an infinfity mass and thius take an infinite amount of energy to achiece.  Secondly, wehave to assume that at the speed of light, your head lights will opperate noramlly (i.e. you turn them on and light shines out) due to [for reasons beyond the scope of this answer] the way head lights actually work.\n\nI would also like to preface my answer with say that traveling AT the speed of light is much different than traveling just UNDER the speed of light.\n\nOne VERY important thing to remember is that in ALL frames of reference, the speed of light is constant.\nNo matter who is watching the light travel and measuring its speed, it will always come out to be the exact some value, 299,792,458 m/s exactly.\n\nWhen you, inside your car traveling at the speed of light (with respect to some "stationary" observer), swtich on your head lights and look out the wind shield, you WILL see light traveling away from you at the speed of light.\n\nIf this "stationary" observer (by which I mean a someone who you are traveling past at the speed of light) watches all this happen, both you and the light are still traveling at the same speed in his reference frame....the speed of light.\n\nSo the answer depends on who's frame of reference your talking about.  From your point of view, yes, you would see the light traveling away from you at the speed of light as if nothing was out of the ordinary.\nFrom the "Stationary" person's reference frame, you and the light would be keeping up with eachother, neither moving infront or falling behind the other one...tied.
706572
The answers already given are generally correct for light travelling in a vacuum. However, the speed of light slows down when it travels through any material substance (the exact amount depends on the material).
468247
The speed of light is constant, approximately 300,000km/second. \n\nThe principals of relative motion are that if you are travelling at a speed, and you look at something else travelling at another speed, your perception of the speed of that something else will be the difference between your two speeds. For example if you are travelling 60, and you get overtaken by someone going at 70, you perceive them to be travelling at 10, since they travelling at 10 relative to you. \n\nHowever, you can never perceive the speed of light to be anything different than it's constant value. Therefore, if you travel at half the speed of light, time actually slows down to half of what it normally is, since this is the only way for the speed of light to remain constant. \n\nTherefore if you travel at the speed of light, time stands still. To answer your question, I don't know what you'd see, but probably nothing!\n\nTheres a more complicated explanation involving the magnetic and electric fields of a photo of light, but that's the basics.
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.)
400598
All of the light "floating" in the air is composed of photons which are eventually absorbed by the atoms in the room and converted into heat.  This heat eventually dissapates through the walls and radiates outside the room.  Of course, there is an imperceptable delay between when the last photon leaves the light and is absorbed by the walls, but this happens at the speed of light and can't be seen by you or me.
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