Optics Question 856

Question: When a plastic thin film of refractive index 1.45 is placed in the path of one of the interfering waves then the central fringe is displaced through width of five fringes. The thickness of the film, if the wavelength of light is 5890Ao , will be

Options:

A) 6.544×104cm

B) 6.544×104m

C) 6.54×104cm

D) 6.5×104cm

Show Answer

Answer:

Correct Answer: A

Solution:

[a]

X0=βλ(μ1)t5β=β(0.45)t5890×1010

t=5×5890×10100.45=6.544×104cm



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