I just get to know that when light passes through optical centre then it shows very very slight deviation which we neglect but when light passes through optical centre then actually light is falling along normal(normal incidence) , in that case angle of incidence is 0 and thus angle of refraction is also 0 (by snell's law) so even that slight deviation should'nt be there( i know it is very very slight deviation, but afterall it is a deviation)

Asked by akshaykhanna6162 | 18th Jun, 2017, 12:38: AM

Expert Answer:

Yes this statement is logically true. But, one should not forget that a lens has a slight thickness near the centre. And for any circle centre is an infinitely small point.We cannot assume an infinitely small centre on the lens and so any light that is incident on the optical centre has to pass through a layer of glass (lens material) due to which there is an ever so small deviation present.
So, basically there are two things to be noted. We neglect deviation because the light is incident on the optical centre perpendicularly. And the second statement is that there is a slight deviation which will be present because the centre cannot be assumed to be infinitely small.

Answered by Romal Bhansali | 1st Nov, 2017, 12:19: PM

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