An unpolarised beam of light is incident on a group of three polarising sheets arranged such that the angle between the axes of any two adjacent sheets is $30^{\circ}$. The ratio of the intensities of polarised light emerging from the second and third sheets is

An unpolarized light of certain intensity passes through a combination of two polarizers whose transmission axes are at $30^\circ$ and $90^\circ$, respectively, with respect to the horizontal axis. $A$ third polarizer with its transmission axis at $60^\circ$ with the horizontal axis is placed between the two existing polarizers. The ratio of the output intensities with and without the third polarizer is . . . . . . .

In the case of linearly polarized light,the magnitude of the electric field vector:

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.

The transverse nature of light is shown by

$A$ beam of light of intensity $I_0$ falls on a system of three polaroids which are arranged in succession such that the pass (transmission) axis is turned through $60^{\circ}$ with respect to the preceding one. The fraction of the incident light intensity that passes through the system is $\left(\cos 60^{\circ} = 1/2\right)$.