Which property can be used to distinguish between light waves and sound waves?

Explain Malus's law and state its mathematical expression.

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.

After passing through a polariser,a linearly polarised light of intensity $I$ is incident on an analyser making an angle of $30^{\circ}$ with that of the polariser. The intensity of light emitted from the analyser will be

Four polaroids are placed such that the optic axis of each is inclined at an angle of $30^{\circ}$ with the optic axis of the preceding one. If unpolarised light of intensity $I_0$ falls on the first polaroid,the intensity of light transmitted from the fourth polaroid is $[\cos 30^{\circ} = \sqrt{3} / 2]$.

When unpolarized light of intensity $I_0$ is incident on a polarizing sheet,the intensity of light that does not pass through is: