Q. 11

# White light is used in a Young’s double slit experiment. Find the minimum order of the violet fringe (λ = 400 nm) which overlaps with a red fringe (λ = 700 nm).

Answer :

Given, and

In this problem, we need to find the distance from the central fringe where the violet and red fringes coincides.

The distance of fringe from the centre is given by

Let the violet fringe overlaps with the red fringe.

Therefore, the seventh violet fringe coincides with the fourth red fringe.

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