Fri November 18, 2011 By:

explain how refraction takes place in a glass slab.Mention the emergent angle for an incidence angle of 30 degree.

Expert Reply
Fri November 18, 2011
It is to do with the light slowing down as it passes into a denser medium. As it slows down it is bent (refracted) and some is turned away (reflected). The sin of the angle of incidence devided by the sign of the angle of refraction is related to the refractive indeces (constants) of the two media concerned
In a nutshell, the speed of light passing through glass is slower than in air due to successive absorption and re-transmission events. The electrons of the glass atoms are doing the absorbing and transmitting.

If refractive index of Glass is 1.5 then
refracive index = sin (angle of incidence)/ sin (angle of refraction)
1.52 = sin 30 / sin (angle of refraction)
sin (angle of refraction) = 1/2 / 1.52 = 1/ 2 * 1.5  = 1/3
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