$A$ ray of light travelling through a rarer medium is incident at a very small angle $i$ on a glass slab,and after refraction,its velocity is reduced by $20 \%$. The angle of deviation is:

What is lateral shift?

$A$ printed page is pressed by a glass of water. The refractive index of the glass and water is $1.5$ and $1.33$,respectively. If the thickness of the bottom of the glass is $1\, cm$ and the depth of the water is $5\, cm$,how much will the page appear to be shifted if viewed from the top (in $,cm$)?

When the same monochromatic ray of light travels through a glass slab and through water,the number of waves in a glass slab of thickness $6 \ cm$ is the same as in a water column of height $7 \ cm$. If the refractive index of glass is $1.5$,then the refractive index of water is:

$A$ container contains a liquid with refractive index of $1.2$ up to a height of $60 \ cm$ and another liquid having refractive index $1.6$ is added to height $H$ above the first liquid. If viewed from above,the apparent shift in the position of the bottom of the container is $40 \ cm$. The value of $H$ is . . . . . . $\ cm$. (Consider liquids are immiscible)

$A$ ray of light is incident on a surface of a glass slab at an angle of $45^{\circ}$. If the lateral shift produced per unit thickness is $\frac{1}{\sqrt{3}}$,the angle of refraction produced is