For light of intensity $I_0$,a polaroid is placed at an angle of $45^\circ$. What will be the intensity of the light passing through the polaroid after polarization?

$V_o$ and $V_E$ represent the velocities,$\mu_o$ and $\mu_E$ represent the refractive indices of ordinary and extraordinary rays for a doubly refracting crystal. Then:

Consider the following statements $A$ and $B$. Identify the correct choice in the given answers.
$A$. The refractive index of the extra-ordinary ray depends on the angle of incidence in double refraction.
$B$. The vibrations of light waves acquire one-sidedness for both ordinary and extraordinary rays in double refraction.

An unpolarised light beam of intensity $2 I_{0}$ is passed through a polaroid $P$ and then through another polaroid $Q$ which is oriented in such a way that its passing axis makes an angle of $30^{\circ}$ relative to that of $P$. The intensity of the emergent light is.

What is a polarizer and an analyser?

An unpolarised beam of intensity $I_{0}$ falls on a polaroid. The intensity of the emergent light is