When one mirror of a Michelson Interferometer is moved a distance of 0.5 mm we observe 2000 fringes. What will be wavelength of light used ?
Correct answer: B. 5000A
- A. 5000 nm
- B. 5000A
- C. 500m
- D. 2000um
Explanation
In a Michelson interferometer, moving one mirror by d changes the optical path by 2d. Thus λ = 2d/N = 2 x 0.5 x 10^-3 m / 2000 = 5 x 10^-7 m = 500 nm = 5000 Å. Students may choose a by confusing 500 nm with 5000 nm and missing the conversion factor.
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Light is studied through reflection, refraction, dispersion, interference, diffraction and polarization, linking ray behavior with its wave nature. Questions may involve mirrors, lenses, optical instruments, refractive index and image formation, while geometrical optics deals with rays and wave optics explains effects such as interference and diffraction.
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