Wave Optics question bank (Physics)

A source produces a light beam of intensity $I_0$ polarized along the $x$-direction. The beam is sent along the $z$-direction. It enters a polaroid $P 1$ with its polaroid axis aligned along the $y$-direction so that no light exits the polaroid. When another polaroid $P 2$ is placed in between the source and $P 1$, the intensity measured after $P 1$ is $3 I_0 / 16$. Which among the following is a possible value of $\theta$, the angle of the polaroid axis measured from the $x$-axis?

Consider a Young's double slit experiment with monochromatic light of wavelength 600 nm . The intensity of the light is $I_0$ at a point on the screen where the path difference is 600 nm . What would be the intensity of light at a point on the screen where the path difference is 100 nm ?