Question

In Young’s double-slit experiment, lights of green, yellow, and orange colors are successively used. Write the fringe widths for the three colors in increasing order.

(a) βG < βY < βO

(b) βO < βY < βG

(c) βO < βG < βY

(d) βY < βG < βO

The question was posed to me during a job interview.

This intriguing question comes from Wave Optics topic in chapter Wave Optics of Physics – Class 12

Answer 1

The correct option is (b) βO < βY < βG

To explain: Fringe width is expressed as:

β = \(\frac {D\lambda }{d}\).

Since the wavelength are related as shown ➔ λG < λY < λO, we can say that ➔ βG < βY < βO.