An unpolarized beam of intensity $2a^2$ passes through a thin polaroid. Assuming zero absorption in the polaroid,the intensity of emergent plane-polarized light is

$A$ beam of unpolarized light passes through a tourmaline crystal $A$ and then it passes through a second tourmaline crystal $B$ oriented so that its principal plane is parallel to that of $A$. The intensity of emergent light is $I_0$. Now $B$ is rotated by $45^{\circ}$ about the ray. The emergent light will have intensity $(\cos 45^{\circ} = \frac{1}{\sqrt{2}})$.

$A$ beam of plane polarized light falls normally on a polarizer of cross-sectional area $3 \times 10^{-4} \, m^2$. The flux of energy of the incident ray is $10^{-3} \, W$. The polarizer rotates with an angular frequency of $31.4 \, rad/s$. The energy of light passing through the polarizer per revolution is:

The phenomenon of polarization shows that light has ......... nature.

In an experiment,two polaroids are arranged such that the intensity of the polarised light emerged from the second polaroid is $37.5 \%$ of the intensity of the unpolarised light incident on the first polaroid. Then the angle between the axes of the two polaroids is (in $^{\circ}$)

When light is incident on a doubly refracting crystal,two refracted rays-ordinary ray ($O$-ray) and extraordinary ray ($E$-ray) are produced. Then: