If the critical angle for total internal reflection from a medium to vacuum is $30^{\circ}$,then the velocity of light in the medium is:

$A$ ray of light propagates from glass (refractive index $= 3/2$) to water (refractive index $= 4/3$). The value of the critical angle is:

For a light ray to undergo total internal reflection ($i =$ angle of incidence,$i_c =$ critical angle):

$A$ beam containing red,green,and blue light is incident on a prism. Their refractive indices are $1.39, 1.44$,and $1.47$ respectively. Then,the prism:

$A$ ray of light passes from a denser medium to a rarer medium at an angle of incidence $i$. The reflected and refracted rays make an angle of $90^{\circ}$ with each other. The angles of reflection and refraction are respectively $r$ and $r^{\prime}$. The critical angle is given by:

$A$ glass prism of refractive index $1.5$ is immersed in water (refractive index $\frac{4}{3}$) as shown in the figure. $A$ light beam incident normally on the face $AB$ is totally internally reflected at the face $AC$ to reach the face $BC$,if: