$A$ camera equipped with a polariser is placed on a mountain to record only the reflected image of the sun from the surface of a sea,as shown in the figure. If the sun rises at $6.00 \, AM$ and sets at $6.00 \, PM$ during the summer,then at what time in the afternoon will the recorded image have the lowest intensity? Assume there are no clouds and the intensity of the sun at the sea surface is constant throughout the day. (Refractive index of water $= 1.33$)

The critical angle of a certain medium is ${\sin ^{ - 1}}\left( {\frac{3}{5}} \right)$. The polarization angle is

$A$ ray of light is incident at a polarising angle such that its deviation is $24^{\circ}$. Then the angle of incidence is: (in $^{\circ}$)

$A$ ray of light is incident on a transparent glass slab of refractive index $1.62$. The reflected and the refracted rays are mutually perpendicular. The angle of incidence is.......$^o$

$A$ 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 $\simeq \frac{4}{3}$)

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