Time taken by light to travel in two different materials A and B of refractive indices μA and μB of same thickness is t1 and t2 respectively. If t2 – t1 = 5 × 10–10 s and the ratio of μA to μB is 1 : 2. Then, the thickness of material, in meter is: (Given vA and vB are velocities of light in A and B materials, respectively.)
5 × 10-10 vA m
5 × 10-10 m
1.5 × 10-10 m
5 × 10-10 vB m
The Correct Option is A
Solution and Explanation
\(\frac{\mu_A}{\mu_B}\)=\(\frac{\frac{c}{V_A}}{\frac{c}{V_B}}\)=\(\frac{V_B}{V_A}\)=\(\frac{1}{2}\)
Let the thickness be d
\(\frac{d}{v_B}\)−\(\frac{d}{v_A}\)=5×10−10
d=5×10−10×\(\frac{v_Av_B}{v_A-v_B}\)
As vA=2vB
⇒d=5×10−10×2vB
Or
d=5×10−10×vA
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Concepts Used:
Light-Dependent Reaction
One of the major surfaces of Light Reaction is giving rise to organic energy molecules, such as ATP and NADPH, which are especially necessary for the subsequent occurrence of the dark reaction that works without the presence of sunlight.
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