In a system of two crossed polarisers,it is found that the intensity of light from the second polariser is half of that from the first polariser. The angle between their pass axes is (in $^{\circ}$)

$A$ polaroid is placed at $45^{\circ}$ to an incoming linearly polarized light of intensity $I_0$. The intensity of light passing through the polaroid after polarization will be:

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.

When an unpolarized light of intensity $I_{0}$ is incident on a polarizing sheet, the intensity of the light which does not get transmitted is

An unpolarized light beam of intensity $I_0$ is passed through a first polaroid $A$ and then through a second polaroid $B$. If the principal plane of polaroid $B$ makes an angle of $45^{\circ}$ with that of $A$,find the intensity of the emerging light.

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: