Wave OpticsHard
Question
In a YDSE experiment if a slab whose refractive index can be varied is placed in front of one of the slits then the variation of resultant intensity at mid - point of screen with ′μ′ will be best represented by (μ ≥ 1).[Assume slits of equal width an there is no absorption by slab]
Options
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B.
C.
D.
Solution
When μ = 1 i.e. no change on path difference due to optical path difference so the mid point of the screen is again the central bright fringe.
But when μ > 1 the central bright fringe will shift according to
(μ - 1) t
As μ increases, CBF will shift upwards from midpoint i.e at mid Less bright fringe appears and when the shift is equal to value of fringe width, the dark fringe (zero intensity ) will appear.
OR
Intensity variation
O ≡ central bright fringe
y ≡ distance from ‘O’ screen
When μ increases, the fringe patterns towards the shift towards the slit when sheet introduced shift 
from the above two fact variation in I with μ is
But when μ > 1 the central bright fringe will shift according to
(μ - 1) tAs μ increases, CBF will shift upwards from midpoint i.e at mid Less bright fringe appears and when the shift is equal to value of fringe width, the dark fringe (zero intensity ) will appear.
OR
Intensity variation O ≡ central bright fringe
y ≡ distance from ‘O’ screen
When μ increases, the fringe patterns towards the shift towards the slit when sheet introduced shift from the above two fact variation in I with μ is Create a free account to view solution
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