Which of the following prisms is used to see the infrared spectrum of light?

$A$ 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.......$^o$.

$A$ ray of light is incident at an angle '$i$' on one face of a thin angled prism. The ray emerges normally from the other face. If the refractive index of the glass prism is '$n$' and the angle of the prism is '$A$',then the value of '$i$' is:

The angle of deviation $\delta$ produced by a prism of refractive index $\mu$ and small refracting angle $A$ is given by:

The angle of minimum deviation for a prism of refractive index $1.5$ is equal to the angle of the prism. The angle of the prism is.......$^o$ (Given: $\cos 41^o = 0.75$)

Two beams of red and violet colours are made to pass separately through a prism (angle of the prism is $60^{\circ}$). In the position of minimum deviation,the angle of refraction will be