Question

In Young’s Double Slit Experiment, if instead of monochromatic light white light is used, what would be the observation?

(a) The pattern will not be visible

(b) The shape of the pattern will change from hyperbolic to circular

(c) Colored fringes will be observed with a white bright fringe at the center

(d) The bright and dark fringes will change position

The question was asked in an interview for job.

Asked question is from Young’s Experiment topic in chapter Interference of Engineering Physics II

Answer 1

Right answer is (c) Colored fringes will be observed with a white bright fringe at the center

To explain: When white light is used instead of monochromatic light in Young’s Double Slit experiment, all the seven constituent colors produce their interference pattern. At the center of the screen, all the wavelengths meet in phase and, therefore, a white bright fringe is formed. Then the next fringe will be formed due to violet color as the wavelength is shortest for violet color. This will be followed by indigo, blue till red color.