How does one demonstrate, using a suitable diagram, that unpolarised light when passed through a polaroid gets polarised?

(a) How does one demonstrate, using a suitable diagram, that unpolarised light when passed through a polaroid gets polarised ?
(b) A beam of unpolarised light is incident on a glass-air interface. Show, using a suitable ray diagram, that light reflected from the interface is totally polarised, when p = tan iB where p is the refractive index of glass with respect to air and iB is the Brewster’s angle

The components of electric vector associated with light wave, along the direction of aligned molecules of a polaroid, get absorbed. As a result after passing through it, the components perpendicular to the direction of aligned molecules will be obtained in the form of plane polarised light.
(b)When an unpolarised light is incident’on the boundary between two Iransperent media, the reflected light is polarised, with electric vector perpendicular to the plane of incidence w’hen the reflected and refracted light rays make a right angle, as shown in the figure below.