Light of wavelength λ1 illuminates a double slit, and interference fringes are observed on a screen behind the slits. When the wavelength is changed to λ2, the fringes get closer together. Is λ2 larger or smaller than λ1?

Answer :

Answer:

λ2 < λ1

Explanation:

- Young's experiment of interference of light when passed through a slit has determined a result. We will use an expression derived from the results that relates wavelength and and the spread of the interference pattern using:

                                            sin (Q) = n*lambda / d

Where,

n is the order of fringe about the central order

lambda is the wavelength of light

d is the space between grating

Q is the angle between the two successive interference fringe

- So in our case using a light of wavelength lambda 2 the pattern got closer together or we could say that angle Q got smaller. According to the relationship given we can see as angle Q decreases when lambda decreases. So we can conclude that  λ2 < λ1.

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