The angle of the prism for which there is no emergent ray will be, if its critical angle is ${ i }_{ c }$

A ray of light is incident on the hypotenuse of a right-angled prism after travelling parallel to the base inside the prism. If $\mu$ is the refractive index of the material of the prism, the maximum value of the base angle for which light is totally reflected from the hypotenuse is :

A given ray of light suffers minimum deviation in an equilateral prism P. Additional prisms Q and R of identical shape and material are now added to P, as shown in the figure. The ray will suffer:

A glass prism of refractive index $1.5$ is immersed in water $(\mu=4/3)$. Light beam incident normally on the face $AB$ is totally reflected to reach the face $BC$ if