Critical Thinking

If $\hat{\mathrm{i}}$ denotes a unit vector along the incident light ray, $\hat{\mathrm{r}}$ a unit vector along refracted ray into a medium of refractive index $\mu$ and $\hat{\mathrm{n}}$ unit vector normal to the boundary of medium directed towards the incident medium, then the law of refraction is

The fine powder of a coloured glass is seen as

A circular disc of which $\frac{2}{3}$ part is coated with yellow and $\frac{1}{3}$ part is with blue. It is rotated about its central axis with high velocity, then it will be seen as

Light enters at an angle of incidence in a transparent rod of refractive index $n$. For what value of the refractive index of the material of the rod the light once entered into it will not leave it through its lateral face whatsoever be the value of angle of incidence?

A glass prism $\left(\mu =1.5\right)$ is dipped in water $\left(\mu =\frac{4}{3}\right)$ as shown in the figure. A light ray is incident normally on the surface $AB$. It reaches the surface $BC$ after total reflection, if

An isosceles prism of angle $120°$ has a refractive index of $1.44\text{.}$ Two parallel monochromatic rays enter the prism parallel to each other in air as shown. The rays emerging from the opposite faces

When light is incident on a medium at angle $i$ and refracted into a second medium at an angle $r$, the graph of $\sin i$ vs $\sin r$ is as shown in the graph. From this, one can conclude that  

Immiscible transparent liquids $A,B,C,D$ and $E$ are placed in a rectangular container of glass with the liquids making layers according to their densities. The refractive index of the liquids are shown in the adjoining diagram. The container is illuminated from the side and a small piece of glass having refractive index$1.61$ is gently dropped into the liquid layer. The glass piece as it descends downwards will not be visible in