Light travels a distance $x$ in time $t_1$ in air and $10x$ in time $t_2$ in another denser medium. What is the critical angle for this medium?

When a ray of light emerges from a block of glass,the critical angle is

Initially,$AB$ is the interface of a slab of refractive index $\mu$ and air. $A$ ray of light strikes $AB$ at the critical angle $\theta_c$. Now,a slab $ABCD$ of refractive index $\mu_1$ is placed on top such that total internal reflection takes place at the surface $CD$ (and not at the surface $AB$). What should be the value of $\mu_1$?

White light is incident on the interface of glass and air as shown in the figure. If only green light undergoes total internal reflection,then the rays in the air are:

For total internal reflection to occur, which one of the following is the correct statement? $(i = \text{angle of incidence}, i_{C} = \text{critical angle})$.

$A$ large glass slab $(\mu = 5/3)$ of thickness $8 \text{ cm}$ is placed over a point source of light on a plane surface. It is observed that light emerges from the top surface of the slab through a circular area of radius $R \text{ cm}$. What is the value of $R$?