An unpolarised light beam strikes a glass surface at Brewster's angle. Then

$A$ ray of light is incident on the surface of a glass plate at an angle of incidence equal to Brewster's angle $\Phi$. If $\mu$ denotes the refractive index of glass with respect to air, then what will be the angle between the reflected and refracted rays?

When unpolarized light is incident from air onto glass $(\mu = 1.5)$,then:

The refractive index of a material is equal to the tangent of the polarising angle. This is called:

Unpolarised red light is incident on the surface of a lake at an incident angle $\theta_{R}$. An observer seeing the light reflected from the water surface through a polariser notices that on rotating the polariser,the intensity of light drops to zero at a certain orientation. The red light is replaced by unpolarised blue light. The observer sees the same effect with reflected blue light at an incident angle $\theta_{B}$. Then,

$A$ person lives in a high-rise building on the bank of a river $50\, m$ wide. Across the river is a well-lit tower of height $40\, m$. When the person,who is at a height of $10\, m$,looks through a polarizer at an appropriate angle at light of the tower reflecting from the river surface,he notes that the intensity of light coming from a distance $X$ from his building is the least,and this corresponds to the light coming from light bulbs at height $Y$ on the tower. The values of $X$ and $Y$ are respectively close to (refractive index of water $\simeq \frac{4}{3}$)