How do mirrors show that light travels in a straight line?
916307
if light did not travel in a staight line then the mirror would make the light refract (focus)and since it does not it proves that light travels in a straight line
682624
Imagine looking through the scope at a star. Every part of the primary mirror is used to form that point of light in the focused image. The blocked light from the secondary simply means it is a tiny fraction dimmer (we won't worry about diffraction at this point). The star next to it is formed the same way --- all of the primary mirror is used to form the dot that is the image of that star.\n\nThis is true all across the field of view. The light from each star strikes all of the primary mirror (except where the secondary blocks it) and all of the primary mirror is used to form that tiny dot of an image. If you think in these terms you can see how there will not be a shadow on one area. Instead, each star is a tiny bit fainter since each star is formed by the light from the whole primary mirror.\n\nNow shift the scope down to a house a mile away. You might think that here the shadow of the secondary would become evident. But the image of each part of the house is formed in the same way. The image of the house is nothing more than a collection of millions of tiny points. The image of each point is formed like the stars --- from the light hitting all of the primary except where the secondary blocks the light. So in essence, the shadow of the secondary is out of focus and is present. It's just that it is equally present across the whole field of view.\n\nIf you look at a field of bright stars, you can quickly verify this. Unfocus the image far enough and you will see the stars expand into disks. go far enough and you will see that each star has the shadow of the secondary.\n\nThe only way to have a shadow cast so that it is clearly seen crossing the field is to put the object in the plane where the image is focused. That's how crosshairs work.\n\nHope this helps\n\nChuck Taylor\nhttp://groups.yahoo.com/group/lunar-observing/
8264
It's because of the minor imperfections in the placement of the mirrors. Also, because the effect can't be seen without seeing it at an angle, it causes a curve based on your viewpoint.
126059
Magnifying mirrors are concaved inward and work by focusing the light on a point such that the image is larger than the original object.\n\nhttp://physics.bu.edu/py106/notes/Spherical.html
618120
The how of refraction is that light travels at different speed in different media, and always takes the minimum time of flight path.\n\nFor example, if you consider a plate of glass with a beam of light hitting it at an angle, like so:\n\n   &#92;&#92;&#92;       Air\n--------------\n    |||      Glass\n\nThe light will bend to travel at a sharper angle as it passes into the glass.  Where exactly it lands ends up being the point that has minimum travel time.  If you were to consider a plane inside the glass parallel to the surface of the glass and calculate, based on the speed in air and the speed in glass, the time it would take the light from the specified source to hit various points on this plane, you'd find the point it actually hits is the one that has the shortest time of flight.  This idea for determining the "why" of refraction originated with the mathematician Fermat, who found that the "principle of least action" applied to many things in physics.   This idea is very similar to the idea of geodesics in modern gravitational theories.\n\nThere are various other ways to calculate this, such as classical methods using Huygen's principle which analyzes the main wavefront into many small wavelets, and considers the action at many points as the incident wavefront meets with material of a different propagation velocity.  The net action of the changes on each wavelet creates a change in direction for the entire wavefront.  \n\nAlso, you can use Feynman's method of considering light taking all possible routes, with the observed route being the phase interference sum of all of these possible routes.  The phase interacts to cancel out all things we *don't* see happen, but, from a quantum mechanical point of view, these non-happening paths are still is a sense real, just very improbable.  So, in that case, the change in path is a result of a Huygen's like phase velocity change, and a phase summation over all possibilities which reinforces the "classical" behaviour.
818655
The glass is poured to the desired thickness, and then silver is applied to the back to give it's reflective surface.  It is then coated with another substance to prevent the light from passing all the way through.  You then see your reflection.\nIn a piece of two way mirror, the silver is applied to the front of the mirror and the other non-reflective substance is omitted.  Thus, you can see all the way through.\nOne good way to tell if you are looking at a piece of two way mirror, is to put your finger up to the glass.  If there is no 'space' between the tip of your finger and the glass...it may be 2-way.  If there is a 'space', it may be only one-way.\nNext time you go into a store, look around for mirrors that appear in the most unusual places.  More than likely, these are 2-way.
1143653
WAVES\n\nLight is a transverse wave. This means that it can be describe as a sinusoidal wave. But not taking that into account, waves spread out into all areas. This is why you can still see things not directly in front of the mirror.
436768
it is only an infinite refrexions of light. the device used to do it is called KALEIDOSCOPE
183503
For instance, astronauts have attached a mirror to a rock on the moon; scientists on earth can aim a laser at this mirror and measure the travel time of the laser pulse--about two and a half seconds for the round trip, which gives about 3.00E8 m/s for the speed of light.\n\nIts speed can also be derived from Maxwell's equations for the speed of propagation of electromagnetic fields in vacuum.
301468
No.\nA straight line is obtained by joining two distinct 'points'.\non this line there lies infinite 'points' between the given end-points.\nSo, a strsaight line is actually a set of POINTS.
115295
I believe it's the percent of light that bounces back and doesnt go through. Like a mirror reflects 95% of light. Dunno could be how much a material bends light, like water, cant remember.
287924
That's because light reflects in the mirror just as if it's coming from the same distance the real object is but behind the mirror.  You are nor looking an image that is at the mirror distance, but really at the real object distance.
917168
The experimental fact verified by experiments with light rays and mirror show that the happenings follow certain laws: If the light ray hits normally it comes back by the same path. If obliquely then it comes back obliquely equally inclined to the normal at the point of incidence and in the same plane of normal and the incident ray. But if you do experiment in which you also measure the intensity of light incident and reflected, then you find that the intensity of reflected light is slightly less. This shows that some light is either absorbed or scattered following no specific laws. Now this is the experimental fact. Now explanations. Explanation depends upon what you assume light to be made up of. If photons, then you know what happens to the table tennis ball when it hits the table without spinning. Same thing should happen to photons. That is how Newton explained  the phenomenon considering light as consisting of particles. He called them corpuscles. But photon is not an ordinary particle in bulk. It is supposed to have dual nature. Its total energy is equal h multiplied by some frequency which is a wave characteristic. Ordinary particle can have all velocities ranging from zero to velocity of light. But photons move with only one  velocity. So in case of bulky table tennis balls we say that they follow these rules of reflection which can be derived from mechanics but lose their little kinetic energy to the table and as sound. In case of photons this is not possible. So we say that if a bunch of photons are incident on a polished surface, there exists a maximum probability of following the laws of reflection, but the probability of the photon getting absorbed or getting scattered in any other direction is vey low but not zero. Similar expalnation can be thought of following the hypothesis that light is electromagnetic wave then we have to take the example of the mechanical waves and see how em wave is differen from them.
18628
Generally household mirrors are a highly reflective silver.  \n\nAnything that is highly reflective can be considered a "mirror" (like the smooth waters of a pond, or a shiny black rock).  More than color, it is smoothness that matters in making a mirror.\n\nA porous surface scatters light in many directions while a smooth surface will reflect light back in a single direction, hence the "mirror" effect.
497011
It works by having little mirror slices at different angles. As light is reflected off the orb, the little slices separates the light into several colours briefly and the process is repeated.
28167
A mirror is a surface with good specular reflection that is smooth enough to form an image. The best known example is the plane mirror. The most common use is in the home for personal grooming but mirrors are also used in scientific apparatus such as telescopes and lasers, and in industrial machinery.\n\n\nIn this diagram plane waves reflect off a parabolic mirror to form waves converging onto a focal point.In a plane mirror, a parallel beam of light changes its direction as a whole, whilst still remaining parallel; the images formed by a plane mirror are virtual images, of the same size as the original object (see mirror image). There are also parabolic concave mirrors, where a parallel beam of light becomes a convergent beam, whose rays intersect in the focus of the mirror. Finally, there are convex mirrors, where a parallel beam becomes divergent, with the apparent intersection occurring behind the mirror. Note that spherical concave and convex mirrors do not have a single focal point, as often described in high school physics text books (see spherical aberration in lens (optics) and aberration in optical systems).\n\nA beam of light reflects off a mirror at an angle of reflection that is equal to its angle of incidence. That is, if the beam of light is shining on a mirror's surface at a 30° angle from vertical, then it reflects from the point of incidence at a 30° angle from vertical in the opposite direction.
812420
if u can trap light in a totally reflective mirror(means which reflect light 100%) and don't make any HOLE in ball it definitely keep on reflecting.\nif mirror is not 100% reflecting it will absorb some portion of light every time light fell on its surface.So after some time light rays will vanish practically.(theoretically light rays will vanish after infinite time)\n \nif yr mirror ball has a hole then there is a probability that light will come out of mirror ball in its journey.\npractically this situation is not possible bcos either second or third situation always applies.