Captain Jack Sparrow tries to observe a fish almost vertically below him in a magical sea of variable refractive index $\mu = y^2 + 1$,where $y$ is the depth below the water surface. Find the apparent depth of the fish below the water level as seen by Captain Jack Sparrow. The actual depth of the fish is $1 \ m$.

The refractive index of water is $1.33$. What will be the speed of light in water?

$A$ mixture of a pure liquid and a solution in a long vertical column (i.e., horizontal dimensions << vertical dimensions) produces diffusion of solute particles and hence a refractive index gradient along the vertical dimension. $A$ ray of light entering the column at right angles to the vertical is deviated from its original path. Find the deviation in travelling a horizontal distance $d << h$, where $h$ is the height of the column.

In the figure shown,the angle made by the light ray with the normal in the medium of refractive index $\sqrt{2}$ is.....$^o$

White light consists of wavelengths ranging from $480 \,nm$ to $672 \,nm$. What will be the wavelength range when white light is passed through glass of refractive index $1.6$?

The optical density of turpentine is higher than that of water,while its mass density is lower. The figure shows a layer of turpentine floating over water in a container. For which of the four rays incident on the turpentine as shown in the figure,is the path correct?