What is a polarizer and an analyser?

For light of intensity $I_0$,a polaroid is placed at an angle of $45^\circ$. What will be the intensity of the light passing through the polaroid after polarization?

The relation $I = I_0 \cos^2 \theta$ is known as (where $I_0$ is the intensity of incident light on the analyser,$I$ is the intensity of emergent light from the analyser,and $\theta$ is the angle between the plane of polarization and the axis of the analyser):

$A$ beam of plane polarised light of large cross-sectional area and uniform intensity of $3.3 \, W m^{-2}$ falls normally on a polariser (cross-sectional area $3 \times 10^{-4} \, m^2$) which rotates about its axis with an angular speed of $31.4 \, rad/s$. The energy of light passing through the polariser per revolution is close to ........ $\times 10^{-4} \, J$.

$A$ $300 \, mm$ long tube contains $60 \, cm^3$ of a concentrated sugar solution. When placed in a polarimeter,it produces an optical rotation of $10^\circ$. If the specific rotation of sugar is $60^\circ$,calculate the amount of sugar in grams present in the tube.

$A$ polarized light of intensity $I_0$ is passed through another polarizer whose pass axis makes an angle of $60^o$ with the pass axis of the former. What is the intensity of emergent polarized light from the second polarizer?