Physics - Wave Optics Question with Solution | TestHub

A screen is at a distance $\mathrm{D}=80\mathrm{cm}$ from a diaphragm having two narrow slits ${\mathrm{S}}_1$ and ${\mathrm{S}}_2$ which are $\mathrm{d}=2\mathrm{mm}$ apart. Slit ${\mathrm{S}}_1$ is covered by a transparent sheet of thickness ${\mathrm{t}}_1=2.5\mu \mathrm{m}$ and ${\mathrm{S}}_2$ by another sheet of thickness $t_2=1.25\mu \mathrm{m}$ as shown. Both sheets are made of material having refractive index $\mu =1.40$. Water is filled in the space between slits and screen. A monochromatic light of wavelength λ = 5000 Å is incident. Calculate ratio of intensity at C to maximum intensity of interference pattern obtained on the screen, where $C$ is foot of perpendicular bisector of $S_1{S}_2$. (Refractive index of water is $\frac{4}{3}$)