Unpolarised light falls on two polarizing sheets placed one on top of the other. What must be the angle between the characteristic directions of the sheets if the intensity of the final transmitted light is one-third the maximum intensity of the first transmitted beam?

$A$ polariser is used to

$A$ plane polarized light is incident on a polarizer with its pass axis making an angle $\theta$ with the $x-$axis,as shown in the figure. At four different values of $\theta$,namely $\theta = 8^o, 38^o, 188^o$ and $218^o$,the observed intensities are the same. What is the angle between the direction of polarization and the $x-$axis in degrees?

Show that when unpolarized light passes through a polarizer,the intensity of the emerging light is half that of the intensity of the incident light.

Three linear polarisers are placed coaxially. The transmission axis of the first polariser is at $30^{\circ}$,the second one is at $60^{\circ}$,and the third at $90^{\circ}$ to the vertical,all in the clockwise sense. Each polariser additionally absorbs $10 \%$ of the light. If a vertically polarised beam of light of intensity $I=100 \, W/m^2$ is incident on this assembly of polarisers,then the final intensity of the transmitted light will be close to ................ $W/m^2$.

How can it be determined whether a given light is unpolarized,plane-polarized,or partially plane-polarized?