Question

In Youngs double slit experiment, a mica slit of thickness t and refractive index $\mu$ is introduced in the ray from the first source ${{S}_{1.}}$ . By how much distance the fringes pattern will be displaced?

• A. $\frac{D}{d}(\mu -1)$
• B. $\frac{d}{(\mu -1)D}$
• C. $\frac{D}{d}(\mu -1)t$
• D. $\frac{d}{D}(\mu -1)t$

Answer 1

Answer: (C)

$\frac{D}{d}(\mu -1)t$

Answer 2

Path difference ${{y}_{p}}=\frac{D}{d}$ Now additional path difference is $(\mu -1)t$ . Therefore displacement will be $\Delta y=\frac{D}{d}(\mu -1)\,t$