Polarized glass is used for sunglasses because...

An unpolarized light beam is incident on the polarizer of a polarization experiment and the intensity of the light beam emerging from the analyzer is measured as $100 \text{ Lumens}$. Now,if the analyzer is rotated around the horizontal axis (direction of light) by $30^{\circ}$ in the clockwise direction,the intensity of the emerging light will be .......... $\text{ Lumens}$.

Two polaroids $A$ and $B$ are placed perpendicularly in the path of a beam of unpolarized light. In between these two,a third polaroid $C$ is placed at an angle of $30^o$ with that of $A$. The percentage of intensity of incident unpolarized light that emerges from $B$ is ........$\%$.

$A$ 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 $\left(\cos 60^{\circ} = 1/2\right)$.

The graph showing the dependence of intensity of transmitted light on the angle between polariser and analyser is ($I_0$ is intensity of plane polarised light)

An unpolarised light of intensity $64 \text{ Wm}^{-2}$ passes through three polarizers successively such that the transmission axis of the last polarizer is crossed with the first. The intensity of the emerging light is $6 \text{ Wm}^{-2}$. The angle between the transmission axis of the first two polarizers is