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

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

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

Three polarising sheets are placed co-axially. The pass axes of polaroids $2$ and $3$ make angles of $30^{\circ}$ and $90^{\circ}$ respectively with the pass axis of polaroid $1$. If $I_0$ is the intensity of unpolarised light entering sheet $1$,what is the intensity of the light emerging from sheet $3$? $(\cos 30^{\circ}=\sqrt{3} / 2, \cos 90^{\circ}=0, \cos 60^{\circ}=1 / 2)$

When unpolarised light is passed through crossed polaroids, then light passing through the first polaroid:

Through which characteristic can we distinguish light waves from sound waves?