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

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

An unpolarized light passes through three polarizing sheets whose polarizing directions make an angle of $30^o$,$60^o$,and $30^o$ with the $y$-axis in the same sense. What fraction of the initial intensity is transmitted by the system?

Unpolarised light of intensity $I_0$ is incident on a polarizer. What is the percentage of the intensity of light that gets transmitted from the polarizer (in $\%$)?

Two polarizers are oriented with their principal planes making an angle of $60^{\circ}$ with each other. The percentage of incident unpolarized light which passes through the system is: (in $\%$)

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)