Question

Suppose I create a two-slit interference pattern using light with some wavelength lambda and slits with some separation D. If I were to increase lambda, what would happen to the interference pattern on the wall? The pattern would spread out Nothing would happen to the pattern The pattern would compress

Answer 1

The pattern would spread out.

Step-by-step explanation:

The fringe width is given by the relation

fringe width = λ L / D where λ is wavelength of light used, L is distance of wall from the source of light and D is slit separation.

If we increase λ , fringe width will increase and therefore pattern will spread out .