Question

In Michaelson interferometer, the position of mirror read 0.6025mm and 0.8970mm for a pair of consecutive bright. Mean wavelength of light is 5393 Å. The difference between the two wavelengths is ___

(a) 3 Å

(b) 4 Å

(c) 5 Å

(d) 6 Å

This question was addressed to me during an internship interview.

I'm obligated to ask this question of Michelson topic in chapter Ultrasonics & Relativity of Engineering Physics I

Answer 1

Correct choice is (d) 6 Å

Easy explanation: d = 0.8970 – 0.6025 = 0.2945 mm

= 2.945 X 10^-4m

λ = 5893 X 10^-10m

λ2–λ1 = \(\frac{\lambda^2}{2d} \)

= 5893 X 5893 X 10^-20/2 X 2.945 X 10^-4

= 6 Å.