Optics Question 845

Question: From a medium of index of refraction n1 , monochromatic light of wavelength λ is incident normally on a thin film of uniform thickness L (whereL>0.1λ) and index of refraction n2 . The light transmitted by the film travels into a medium with refractive index n3 .The value of minimum film thickness when maximum light is transmitted If (n1<n2<n3) is

Options:

A) n1λ2n2

B) n1λ4n2

C) λ4n2

D) λ2n2

Show Answer

Answer:

Correct Answer: B

Solution:

[b] Equation of path difference form maxima in transmission (or weak reflection)

ΔPopt=2n2L=λvacuum2,3λvacuum2.

2(n2n1)

L=λ2 , 3λ2L=λ4n2

(notice that λ = wavelength in medium is related to λvacuum as, λvacuum=n1λ )



जेईई के लिए मॉक टेस्ट

एनसीईआरटी अध्याय वीडियो समाधान

दोहरा फलक