Question

In Young’s double-slit experiment, what happens to the spacing between the fringes if (a) the slit separation is increased? (b) the wavelength of the incident light is decreased? (c) if the distance between the slits and the viewing screen is increased?

Answer 1

The expression for the fringe spacing, y is –

y = (lemda * L) / d-----------------------------------------(i)

where, lemda = wavelength of the incident light

L = distance between slit to the screen

d = distance between the slits.

(a) when slit separation ‘d’ is increased in the expression (i), the fringe spacing ‘y’ will decrease.

(b) when wavelength of light ‘lemda’ will decrease, the fringe spacing ‘y’ will decrease.

(c) ) when the distance between the slit and the viewing screen is increased, the fringe spacing ‘y’ will also increase.