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The Blue Sky When sunlight passes through earth’s atmosphere a considerable amount of it is absorbed by the air molecules and hence sets the molecules of air in vibration due to which the direction of light waves is changed. Further short light waves are scattered least and vice-versa, so red light is scattered least and orange, yellow, green, blue and lastly violet follows it; it is clear that violet light scatters maximum. This combination as given below produces light blue color of the sky. Violet Blue
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submitted by N.Utk (7 m) on 6 Sep 2008 12:25:32 IST (1 comments 28 views)
hey guys we have been learning wrong optics all so longdon't beleive me see it for yourself according to total internal reflection (topic) , if angle of incidence increases in the rarer medium than at a point angle of refraction becomes 90 then at that point refracted ray should be parallel exactly to the interface -----by applying pronciple of reversibility of light - - - - - - light ray which is parallel to interface boundry shoul
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submitted by ikchugh (153 m) on 11 Jun 2008 03:17:31 IST (2 comments 241 views)
Recently, i read few posts saying that Snells law fails for normal incidence...I Disagree...There are two ways of looking at it..1)U have two media with u1/u2=u.applying snells law, we get 0/0 form... This is indeterminate form. so, it can assume any value...But, treating determainate forms can be complex and this is one way out- since it can assume any value, for your case it will assume the value of the refractive index you consider!!! Its difficult to agree, but its one way out...2)now, looking in different way,What does an indeterminate answer imply...It implies the case is universal and irrespective of the media chosen, which is correct.. So, snells gives
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submitted by nikhil_bafna (512 m) on 2 Jun 2008 01:05:13 IST (13 comments 184 views)
Formulas for single lens (in air) Coding rule of lenses (when light moves from left to right) Focal length of two ideal lenses Numerical aperture(Numerical Aperture : NA) F number Theoretical spot diameter of lens Focal length of concave mirror Magnification of beam expander Light refraction (Snell?fs law) Light shifted by parallel windows Ang
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submitted by coolriya (482 m) on 18 Apr 2008 21:42:50 IST (3 comments 121 views)
some formulas in optics 1) = 2pi (x) / lamda = phase diff. ................del. x is path diff. 2)normal shift S = t (1 - 1/).....................( is not whole divided) Swater = t/4 Sglass = t/3 3)wen a lens is cut into 2 = parts perpendicular to its principal axis , focal length gets doubled and power gets halved 4)wen a lens is cut into 2 = parts parallel to its P. Axis , no change in focal length or power takes place 5)Goggles donot hav any power coz R1 = R2 = R for them
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submitted by chimanshu_007 (11535 m) on 16 Apr 2007 11:09:13 IST (30 comments 1818 views)
The Law of Reflection When a ray of light strikes a plane mirror, the light ray reflects off the mirror. Reflection involves a change in direction of the light ray. The convention used to express the direction of a light ray is to indicate the angle which the light ray makes with a normal drawn to the surface of the mirror. The angle of incidence is the angle between this normal and the incident ray; the angle of reflection is the angle between this normal and the reflected ray. According to the law of reflection, the angle of incidence equals the angle of reflection. These concepts are illustrated in the animation at the right.. Image Fo
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submitted by master_purav (1343 m) on 9 Sep 2007 15:20:19 IST (3 comments 126 views)
eclipse shadow of wine glass on white paper image of a girl in the bubble who is playing in a garden(right at the centre) inverted images of ayers rock in the background sunflower field as seen through a magnifying glass
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submitted by bhuvana89 (1051 m) on 4 Jul 2007 11:42:18 IST (4 comments 168 views)
Eyepieces come in several diameters: 0.96 inches, 1.25 inches, and 2 inches. The 0.96 inch eyepieces are generally found on cheap department store telescopes, I would not recommend buying a telescope only capable of using them, as they can be very difficult to find. The more common sizes are 1.25" and 2.0". Eyepieces not only vary in size, and focal length but also in design. The simple designs give acceptable performance and in some cases even excellent performance. Galileo, Kepler and Newton didn't have too many choices when they were picking
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submitted by raman_shadow (754 m) on 19 May 2007 16:54:37 IST (3 comments 104 views)
HALOS:WHAT"S happening?A 22° halo is a rather frequently appearing halo, an optical phenomena forming a circle 22° around the sum, or occasionally the moon. It forms as sunlight is refracted in hexagonal ice crystals suspended in the atmosphere. As the light beam passes through two sides of the prism forming a 60° angle, the angle of minimum deviation is almost 22° (e.g. 21,84° in average; 21,54° for red and 22.37 for blue.) This wavelength-dependent variation in refraction causes the inner edge of the circle to be reddish while the outer edge is bluish.you can see them quite often if you look carefully and by using sunglasses while looking for them around the sun.
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submitted by vagee (133 m) on 5 May 2007 20:54:36 IST (3 comments 127 views)
1)If aperson is at some dist. frm a mirror of C = d and he is passing by then he can see his image upto dist. 3d 2)formation of rainbow is due to T.I.R. and refraction 3)but twinkling of stars is due to refraction only 4)moons look bigger due to optical illusion only 5)the time taken by a light ray to pass through a transparent plate of a thichness t and R. I . = # is T = #T/C 6)in a vaccum all colours travel wid same vel. but in a medium red travels fastest 7)if we write all the colour names wid respective colours (eg. red wid red, voilet wid voilet and see it through a slab then the colour
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submitted by chimanshu_007 (11535 m) on 18 Apr 2007 12:50:11 IST (8 comments 349 views)
