Optics Problems - Numerical 26

26.

In Young's double slit experiment, we observe the 10^th maximum for l = 1000^o A. What will be visible if the source of light is replaced by light of wavelength 5000^o A

Suggested solution:

If y₁₀ be the distance of the 10^th bright fringe from the central fringe, then,

Let n^th bright fringe be formed at the same place when the new wavelength is 5000 A

But y_n = y_{10 (given)}

On simplification, n=14

Thus, 14^th order bright fringe will be visible at the same place where 10^th order bright fringe was originally observed.