$A$ 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 $25 \%$. The angle of deviation is:

$A$ 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 $,cm$)?

$A$ beaker contains water up to a height $h_{1}$ and kerosene of height $h_{2}$ above water. The total height of (water $+$ kerosene) is $(h_{1} + h_{2})$. The refractive index of water is $\mu_{1}$ and that of kerosene is $\mu_{2}$. The apparent shift in the position of the bottom of the beaker when viewed from above is:

$A$ diverging beam of light from a point source $S$ having divergence angle $\alpha$,falls symmetrically on a glass slab as shown. The angles of incidence of the two extreme rays are equal. If the thickness of the glass slab is $t$ and the refractive index is $n$,then the divergence angle of the emergent beam is

What is lateral shift?

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 $5 \ cm$ is the same as in a water column of height $6 \ cm$. If the refractive index of glass is $1.56$,then the refractive index of water is: