Question

A transparent film of thickness $t$ and refractive index $\mu$ is placed in front of one of the slits in a Young's double slit experiment. As a result, the interference pattern shifts through a distance $S$. Which of the following graphs correctly represents the variation of $S$ with $t$, as other parameters remain constant?

• A.
• B.
• C.
• D.

Answer 1

The correct option is C

The shift in the interference pattern is, $S=\frac{D}{d}(\mu -1)t$

As other parameters remain constant, the shift is directly proportional to the thickness $t$. So the graph of $S$ Vs $t$ will be a straight line.
Also, when $t=0,S=0$.

Hence, $\left(C\right)$ is the correct answer.