Which of the following diagrams represents the variation of the electric field vector magnitude with time for a circularly polarized light?

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.

Two linear polarisers are placed coaxially. The transmission axis of the first polariser is at $30^{\circ}$ from the vertical,while the second one is at $60^{\circ}$ from the vertical,both in the clockwise sense. If an unpolarised beam of light of intensity $I_{0}=20 \,W/m^{2}$ is incident on this pair of polarisers,then the intensities $I_{1}$ and $I_{2}$ transmitted by the first and second polarisers respectively,will be close to:

The angle between the polarizer and the analyzer is $45^o$. The percentage of polarized light passing through the analyzer is........$\%$

$A$ plane polarized light is incident normally on a tourmaline plate. Its $\vec{E}$ vectors make an angle of $60^{\circ}$ with the optic axis of the plate. Find the percentage difference between initial and final intensities. (in $\%$)

Two polaroids are oriented with their planes perpendicular to incident light and transmission axis making an angle $30^{\circ}$ with each other. What fraction of incident unpolarised light is transmitted (in $\%$)? $(\cos 30^{\circ} = \sqrt{3} / 2)$