what is the purpose of ray diagrams in physics?
451784
in physics we use ray diagrams to study optics. By ray diagrams one is able to study and understand various cases of refraction, reflection etc.
169706
the angle between the incident ray and the perpendicular to the reflecting or refracting surface at the point of incidence
913177
Yes there are, and the best (imho) explanations in plain, non-technical language are in a book by Richard Feynmann titled  "QED The strange theory of light and matter".\nWhen you first read what actually happens when light bounces off a mirror it's mind blowing. There are equally good explanations of why a simple lens works, etc.
145216
A ray is a line that has a definite starting point and extends infinitely in only one direction.  A line extends infinitely in both directions.  A line segment has a specific beginning and ending point.\n\nLine <---------------------->\n\nLine segment *--------------*\n\nRay *--------------->
436857
Good question. \n\nIt's just notation. Just like why do we show potential energy by U? Why do we show density by "rho"?
737899
Mostly used in science, you familiar with it displaying the rainbow with white light, it can also be used to indentify other colors of light a gases.  When using it to identify gases, you will see the rainbow, but with a line of color missing called the "absorption lines" scientists have developed a chart to referece this.  For example, Cholorine will show all the colors but a line a blue/purple will be misssing, they can reference their documents and know what gas it is.  Here is a picture I found about it,\n\nhttp://en.wikipedia.org/wiki/Image:Cumulative-absorption-spectrum-hubble-telescope.jpg\n\nMany people suppose that the main optical action of a prism is to disperse white light into its component parts, because that's what Isaac Newton used prisms for. But because dispersion is really a very small effect, it isn't the main optical action of a prism; more correctly, it should be looked at a a minor side effect. \n\nThe main effect of a prism is to deviate a beam of light. But, because of the dispersion in the refractivity of transparent materials, the deviation is slightly different for light of different colors. This slight difference in the deviation — only one or two percent, typically — is where the dispersive power of a prism comes from. \n\nIn optics, prisms made for the purpose of dispersing light are usually made with bases that are equilateral triangles, so that the angles between adjacent sides of the prism are 60°. However, prisms are also often used to re-direct light by using internal reflection; these often have bases that are isosceles right triangles, with angles of 45°-90°-45°. As optical technology developed, opticians found uses for more complicated pieces of glass with plane entrance, exit, and reflecting or refracting faces; but these are often not “prisms” in the geometric sense, but more complicated polyhedra, or even more complex shapes, with unused corners cut or rounded off to reduce weight.
1113065
It's just a means of easily displaying the relfections of the ultrasonic system so the operator can see the echoes in a relatively easy to understand way. The operator will be able to make a better judgement of where the edges of the steel are from the scope trace than an electronic meter could which could get confused by different traces/echoes.
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.
980985
They are simply arrows that show the direction a force is applied in (by seeing what direction the arrow points) and how big the force is (magnitude) by how long the arrow is.  So if one vector is twice as long as another, it represents twice the force of the other.
800086
Rather, by drawing a ray diagram you will see tt since the object is placed BETWEEN the focal point and the 'second focal point' (which is 2 x the focal length from the verticle), the image formed will be real, magnified and inverted.\n\nYou may want to check out the other variations for objects placed BEFORE the focal point, AT the focal point, AT 2 focal points away, or BEYOND 2 focal points as well.\n\nI dunno of any equation but i doubt there are any. the answer to ur qn is more of how does the object looks like. and to find out the size of the image it very much depends on the lens used. and perhaps you can apply some trigo.
1103302
Assume you have a number line, and through the origin (0) of that number line, you place another number line perpendicular to the first, so that the second origin is the same point as the first origin.  Now you have a [rectangular/Cartesian] coordinate plane.\nYou denote a point by measuring its distance along the horizontal axis from the origin, and then measuring its distance along the vertical axis from the origin and coming up with notation like (8,4).  It's 8 "to the right" and 4 "up" from the origin.\nWe use this plane to graph lines, circles, hyperbolas, parabolas, ellipses, etc.\n\nIf you don't want to get confused, stop reading here.\n\nThere is also a [circular/polar] coordinate plane, wherein you take a number line, and chop off half of it at the origin, so it's a ray.  The first coordinate is the distance from the origin along that ray.  The second coordinate is the measure of the angle you would make with the ray, and a second ray passing starting at the origin and including the point in question [typically measured in radians, so pi radians is 180°].  Like (4, 0) is 4 units "to the right" of the origin and (4,pi) is 4 units "to the left" of the origin.\nThis coordinate system is useful for graphing spirals and other looping curves.
623587
It's a method of solving mechanical problems. Basically it's determined by L = T - V where T is the kinetic energy and V the potential. Finding T and V really depends on the problem. You use generalized coordinates, normally denoted by q, as opposed to x, y, z or whatever. Once you get the hang of it it can be extremely useful to solve seemingly difficult mechanical problems (like a pendulum on a pendulum for example.) Look it up on Wikipedia for more information.
213752
It's a way of expressing something in unitless terms.  Very important for statistics and probability.  Also useful for comparing two numbers of the same unit.
931671
it's just a symbol to indicate\na right angle-hit the site below\nfor more details of angles etc\n\nhttp://www.coolmath.com/\n\ni hope that this helps
353539
For recent physics and maths preprints, try here\n\nhttp://lanl.arxiv.org/\n\nor one of it's mirror sites
99922
It might be helpful to indicate which theorem you are talking about.  After all, Chebyshev derived hundreds of results and theorems.
16574
It could be a plugin for viewing 3D files (earlier versions were called Metastream). I'd say if you're not using it, nuke it.