Of course, it is the law after all.
I believe what you're really wondering is why do sources define the focal point as R/2 for incoming rays that are "close," and parallel to, the optical axis. I haven't found this anywhere else, but I worked out the intersection of the optical axis and incoming rays parallel to it just now.
For incident angles less that 60 degrees, the intersection is equal to:
R=radius
i=incident angle; this is in respect to the normal, as always.
r*cos(i)/[1+cos(2*i)]
Rounding to four decimal places, there is ~21.32 percent difference between the average of this and the R/2 method. It's ugly, but it's a lot easier. So, using the R/2 method will focus ~59.73% of the light captured. Very ugly, indeed.
This is all according to my own work, of which has never been reviewed. Interestingly enough, light with a 60 degree i will exit parallel to the optical axis (and r*sqrt(3)/2 opposite of it's side of entry).
A concave mirror is a spherical mirror which is curved inward, where the inside surface is reflective. They work by reflecting the light captured into the centre of the mirror, creating a focal point in the centre of the mirror.
it reflects light which bounces back and makes a refletion
mirror works with the phenomenon of reflection but not the phenomenon of refraction .when the light rays are reflected only the image is formed .
Descartes explains the logic behind the laws of reflection he discovered in his work "Dioptrics". He uses the idea of a tennis ball bouncing at an angle of the ground and up through a sheet to formulate the laws of reflection on a geometric plane.
When a photon of light hits a mirror it cause the electrons in the mirror's atoms to vibrate and give off identical photons of light. Metals work better as mirrors because they have a large number of
Reflection works best if it is on a smooth shiny surface.
Pretty much everything you see. The fact we can see is due to light reflecting off of objects and into our eyes. A good example, I guess, is the moon. When it glows at night, that is just light from the sun reflecting onto the Moon's surface, and bouncing back, giving it that glow. Another great example is: Seeing your hand in front of your face. Others are: -- seeing an image of yourself in the mirror -- looking at the car ahead of you when you're driving -- reading the newspaper -- looking at your wife's face -- looking at what buttons you're pushing when you make a phone call -- finding your shoes in the bedroom -- figuring out which house to walk into after school or work
The Cassegrain has a hole in the mirror, at the bottom of the scope, where the reflector mirror reflects the light onto the viewing piece. So, the Cassegrain is a reflection telescope but it's primary and secondary mirrors work a bit differently than most reflecting telescopes.
When light hits a mirror , it will be reflected symetrically to a normal . Tangents are not really used to figure out the light bending . If the light hits a round surface ( Still a mirror ) , you must draw a tangent and the normal of this tangent . Then , you work it out just like if it was a plane mirror . You cannot calculate light bending on something else than a mirror, but there is sometime a total reflection on glass or any similar substance . ( Same technique ) http://www.youtube.com/watch?v=4VmMr9TWzY4 http://id.mind.net/~zona/mstm/physics/light/rayOptics/reflection/r1.jpg
spherical, ovoid, cylindrical.
No.
It all depends on if the telscope is a refractor, or a reflector. Reflectors have a convex mirror that bends the reflection on to a flat mirror that angles the magnified reflection to the eyepiece. Refractors use to convex lenses that bend the image and light, magnifying the view to the eypiece.