In Young's double slit experiment if monochromatic light is replaced by white light

Options

A. no fringes are observed
B. only central fringe is white, all other fringes are coloured
C. all bright fringes become white
D. all bright fringes have colours between violet and red.

Answer

B

Explanation

When a source in Young.s double slit experiment is white, the central fringe is white as all colours meet there inplace, phase difference is zero. Whenever the values of wavelength (colour) satisfy the conditions for constructive interference, one gets coloured fringes. Some can even overlap at higher orders