Optics Question 861
Question: In YSDE, both slits are covered by transparent slab. Upper slit is covered by slab of R.I. 1.5 and thickness t and lower is covered by R.I. $ \frac{4}{3} $ and thickness 2t, then central maxima
Options:
A) shifts in +ve y-axis direction
B) shifts in -ve y-axis direction
C) remains at same position
D) may shift in upward or downward depending upon wavelength of light
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Answer:
Correct Answer: B
Solution:
[b] $ \Delta x _{1}=({\mu _{1}}-1)t=(1.5-1)t=0.5t $
and $ \Delta x _{2}=({\mu _{2}}-1)\times 2t=( \frac{4}{3}-1 )\times 2t=\frac{2}{3}t $
As $ \Delta x _{2}>\Delta x _{1} $ , so shift will be along -ve v-axis.