Describe fresnel biprism and the angle of biprism.

A plane light wave with wavelength $\lambda =0.70 \mathrm{\mu m}$ falls normally on the base of a biprism, made of glass $(n=1.520)$ with refracting angle $\mathrm{\theta }=5.0°$. Behind the biprism there is a plane-parallel plate, with the space between them filled up with benzene $\left(n\text{'}=1.500\right)$. Find the width of a fringe on the screen $Sc$ placed behind this system.

Represent the union of two sets by Venn diagram for each of the following.

$X=\{x | x$ is a prime number between $80$ and $100\}$

$Y=\{y | y$ is an odd number between $90$ and $100\}$

For the biprism experiment shown in the figure, the fringe width does not increases when