$A$ thin prism $P_1$ with angle $4^o$ and made from glass of refractive index $1.54$ is combined with another thin prism $P_2$ made from glass of refractive index $1.72$ to produce dispersion without deviation. The angle of prism $P_2$ is......$^o$

$A$ ray of monochromatic light is incident on one refracting face of a prism of angle $75^o$. It passes through the prism and is incident on the other face at the critical angle. If the refractive index of the material of the prism is $\sqrt{2}$,the angle of incidence on the first face of the prism is.......$^o$.

$A$ prism is made up of a material with a refractive index of $\sqrt{3}$. The angle of the prism is $A$. If the angle of minimum deviation is equal to the angle of the prism,then the value of $A$ is: (in $^{\circ}$)

When light of wavelength $\lambda$ is incident on an equilateral prism kept in its minimum deviation position,it is found that the angle of deviation equals the angle of the prism itself. The refractive index of the material of the prism for the wavelength $\lambda$ is,then

$A$ prism is made up of material of refractive index $\sqrt{3}$. The angle of the prism is $A$. If the angle of minimum deviation is equal to the angle of the prism,then the value of $A$ is: (in $^{\circ}$)

$A$ deviation of $5^o$ is observed from a prism whose angle is small and whose refractive index is $1.5$. The angle of the prism is.......$^o$