$A$ ray of light travelling in a transparent medium falls on a surface separating the medium from air at an angle of incidence of $45^\circ$. The ray undergoes total internal reflection. If $n$ is the refractive index of the medium with respect to air,select the possible value$(s)$ of $n$ from the following:

Assertion: Diamond glitters brilliantly.
Reason: Diamond does not absorb sunlight.

The figure shows a mixture of blue,green,and red colored rays incident normally on a right-angled prism. The critical angles of the material of the prism for red,green,and blue are $46^{\circ}$,$44^{\circ}$,and $43^{\circ}$ respectively. The arrangement will separate:

$A$ point source of light is placed $4 \; m$ below the surface of water of refractive index $5/3$. The minimum diameter of a disc which should be placed over the source on the surface of water to cut-off all light coming out of water is ... $m$.

$A$ point source $S$ is placed at the bottom of different layers as shown in the figure. The refractive index of the bottom-most layer is $\mu_0$. The refractive index of any other upper layer is $\mu(n) = \mu_0 - \frac{\mu_0}{4n - 18}$,where $n = 1, 2, \dots$. $A$ ray of light with an angle of incidence $i$ slightly more than $30^\circ$ starts from the source $S$. Total internal reflection takes place at the upper surface of a layer having $n$ equal to

$A$ wide container is filled with water $\left(\mu=\frac{4}{3}\right)$ up to a height of $1 \ m$. Find the diameter of the disc at the top of the water surface from which light is coming out.