what is the definition of total internal reflection?
90831
Lesson 3: Total Internal Reflection\nTotal Internal Reflection\nAn unusual observation - a discrepant event - was observed in a recent lab - the Index of Refraction lab. The refraction of light through a glass block in the shape of an isosceles triangle was investigated (at least, so we thought). In the lab, a ray of light entered the face of the triangular block at a right angle to the boundary. This ray of light passed across the boundary without refraction since it was incident along the normal (recall the Secret of the Archer Fish). The ray of light then traveled in a straight line through the glass until it reached the second boundary. Only instead of transmitting across this boundary, the entirety of the light seemed to reflect off the boundary and transmit out the opposite face of the isosceles triangle. This discrepant event bothered many as they spent several minutes looking for the light to refract through the second boundary. Then finally, to their amazement, they looked through the third face of the block and could clearly see the ray. What happened? Why did light not refract through the second face?\n\n\nThe phenomenon observed in this part of the lab is known as total internal reflection. Total internal reflection, or TIR as it is intimately called, is the reflection of the total amount of incident light at the boundary between two medium. TIR is the topic of focus of Lesson 3.\n\nTo understand total internal reflection, we will begin with a thought experiment. Suppose that a laser beam is submerged in a tank of water (don't do this at home) and pointed upwards towards water-air boundary. Then suppose that the angle at which the beam is directed upwards is slowly altered, beginning with small angles of incidence and proceeding towards larger and larger angles of incidence. What would be observed in such an experiment? If we understand the principles of boundary behavior, we would expect that we would observe both reflection and refraction. And indeed, that is what is observed (mostly). But that's not the only observation which we could make. We would also observe that the intensity of the reflected and refracted rays do not remain constant. At angle of incidence close to 0 degrees, most of the light energy is transmitted across the boundary and very little of it is reflected. As the angle is increased to greater and greater angles, we would begin to observe less refraction and more reflection. That is, as the angle of incidence is increased, the brightness of the refracted ray decreases and the brightness of the reflected ray increases. Finally, we would observe that the angles of the reflection and refraction are not equal. Since the light waves would refract away from the normal (a case of the SFA principle of refraction), the angle of refraction would be greater than the angle of incidence. And if this is the case, the angle of refraction would also be greater than the angle of reflection (since the angles of reflection and incidence are the same). As the angle of incidence is increased, the angle of refraction would eventually reach a 90-degree angle. These principles are depicted in the diagram below.\n\n\nThe maximum possible angle of refraction is 90-degrees. If you think about it (a practice which always helps), you recognize that if the angle of refraction were greater than 90 degrees, then the refracted ray would lie on the incident side of the medium - that's just not possible. So in the case of the laser beam in the water, there is some specific value for the angle of incidence (we'll call it the "critical angle") which yields an angle of refraction of 90-degrees. This particular value for the angle of incidence could be calculated using Snell's Law (ni=1.33, nr=1.000, =90 degrees, = ???) and would be found to be 48.6 degrees. Any angle of incidence which is greater than 48.6 degrees would not result in any refraction. Instead, when the angles of incidence is greater than
639495
Anything is visible beacuse either light emitted from it, or light reflected from it reaches our eyes. If light passes through something completely, it will not be reflected to our eyes, and the object will become transparent or invisible. Glass comes very near this.
986686
It is how opaque a material is.\n\nIt is measured by how much light can be seen through the material.
745196
What you are describing is a result of light reflecting off a concave surface.  The best way to explain this is like this:\n\nDraw a big T on a piece of paper.\nNow draw a line from the lower right side to the vertex of the T (that's the intersect).  This represents light coming in.\nNow draw another line from the vertex to a point at the same location as the origin of the other line, but on the lower left.  That is the light leaving.  The angles of both lines converging on the crossing of the T should be the same.  Same with any beam of light.  It is reflected at the same angle as it is received.\n\nA spoon is a reflecting concave mirror.  If you could get close enough to the spoon you could see your image right side up.  But when you are further out than the focal distance the image inverts because the beams cross over each other.
505113
Reflection off of smooth surfaces such as mirrors or a calm body of water leads to a type of reflection known as specular reflection. Reflection off of rough surfaces such as clothing, paper, and the asphalt roadway leads to a type of reflection known as diffuse reflection.\n\nGood luck doing your homework!
682849
All colors...or clear.\n\n\nTechnically, there's no true color.  The backing surface, behind the glass part, is a reflective silver-esque color, but it reflects light perfectly, which makes the person believe that it has all color properties.  Howevever, since light holds a wide array of colors, the mirror is simply reflecting all colors.  But since it requires light to show color, and it doesn't stay static in it's color reflection, it doesn't exactly have any one color.
922899
Points to consider:\nFocal distance of mirror.\nMirror type: Flat, concave and convex.\nReflected index of silver coating.\nMagnification of image.\nGlass type.\nGlass colour.\nThickness of glass used.
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,
441007
Lighty is an electromagnetic ray that gives the sensation of sight.Electromagnetic waves are waves that donot need any material medium for their propogation.\n\n\nWhen a light falls on a polished surface like mirror reflection occures and this phenominon is called reflection\n\nWhen a light falls on a transparent substance like water  and glass it passes throuhg that medium and this phenominon is called refraction\n\nMagnification is the ratio of the size of the image to the size of the object
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.
799966
the external angle\n\ni hope that this helps
304013
~4% of light is reflected back at normal incidence (standing in front of the mirror).  In order to see the reflected image of yourself, the light that is reflected should be brighter than any light coming through the glass.  If the glass is black, it means that little light passes through it, so it should be fairly easy to see your image.  This is also why it it is easier to see your image in transparent glass if it is brighter in the room on your side of the glass than on the other side.
1075466
This phenomenon is call total internal reflection.\nThe theory explaining the phenomenon is detailed in most good physics optics textbooks.
811482
possibly illogical statement\n\ntransparent means we can see through it
414316
Hi,\nThe answer is C.\n\nYou could make a ray-diagram and see for yourself...
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.
620878
focal length = infinity\ncurvature  = 0