The minimum value of the refractive index for a 90° – 45° – 45° prism which is used to deviate a beam by 90° by the phenomenon of total internal reflection is ____

Q. What is the minimum value of the refractive index for a ${90}^{\circ }–{45}^{\circ }–{45}^{\circ }$ prism
which is used to deviate a beam through ${90}^{\circ }$ by total internal reflection ?

Q. A light ray is incident perpendicular to one face of a ${90}^{\circ }$ prism and totally internally reflected at the glass interface. If the angle of reflection is ${45}^{\circ }$. The refractive index is :

Q. A parallel beam of light is incident from air at an angle a on the side $PQ$ of a right-angled triangular prism of refractive index $n=\sqrt{2}$. The beam of light undergoes total internal reflection in the prism at the face $PR$ when a has a minimum value of ${45}^{\circ }$. The angle $\theta$ of the prism is

Q. A light ray is incident perpendicular to a face of a ${90}^{\circ }$ prism and is totally internally reflected at the glass – air interface. If the angle of reflection is ${45}^{\circ }$, what can be concluded about the refractive index n?

Q. A parallel beam of light is incident from air at an angle $\alpha$ on the side PQ of a right-angled triangular prism of refractive index $n=\sqrt{2}$. Light undergoes total internal reflection in the prism at the face $PR$ when $\alpha$ has minimum value of ${45}^{\circ }$. The angle $\theta$ of the prism is