Question

A Young's double-slit experimental set up is kept in a medium of refractive index `(4/3)`. Which maximum in this case will coincide with the 6^th maximum obtained if the medium is replaced by air?

Options

• 4^th

• 6^th

• 8^th

• 10^th

Answer 1

8^th

Explanation:

Position of n^th bright fringe,

`x_n = (n lambda D)/(mud)`

For 6th maximum in air, (µ = 1)

`x_6 = (6 lambda D)/d`

For n^th maximum in medium, `(mu = 4/3)`

`x_n"'" = (3nlambdaD)/(4d)`

Now, x_n' = x₆

`(3nlambdaD)/(4d) = (6lambdaD)/d`

⇒ n = 8