$A$ thin prism of angle $6^{\circ}$ made of glass of refractive index $1.5$ is combined with another prism made of glass of refractive index $1.75$ to produce dispersion without deviation. Then, the angle of the second prism is (in $^{\circ}$)

The critical angle between an equilateral prism and air is $45^o$. If the incident ray is perpendicular to the refracting surface,then

For refraction through a small angled prism,the angle of deviation:

Three prisms $1, 2$ and $3$ have the prism angle $A = 60^o$,but their refractive indices are respectively $1.4, 1.5$ and $1.6$. If $\delta_1, \delta_2, \delta_3$ be their respective angles of deviation,then:

$A$ ray of light is incident normally on the first refracting face of a prism of refracting angle $A$. The ray of light comes out at grazing emergence. If one half of the prism (shaded portion) is knocked off,the same ray will:

In an experiment for the determination of the refractive index of glass of a prism by an $i - \delta$ plot,it was found that a ray incident at an angle of $35^o$ suffers a deviation of $40^o$ and emerges at an angle of $79^o$. In that case,which of the following is closest to the maximum possible value of the refractive index?