The refractive index of air is $1.0003$. The thickness of an air column that will contain one more wavelength of yellow light $(6000 \mathring A)$ than in the same thickness in a vacuum is:

Explain rarer and denser medium.

What is refraction of light? Explain the laws of refraction.

The ratio of the thickness of plates of two transparent mediums $A$ and $B$ is $6 : 4$. If light takes equal time in passing through them,then the refractive index of $B$ with respect to $A$ will be:

$A$ large square container with thin transparent vertical walls and filled with water (refractive index $\mu = \frac{4}{3}$) is kept on a horizontal table. $A$ student holds a thin straight wire vertically inside the water at a distance of $12 \ cm$ from one of its corners,as shown in the figure. Looking at the wire from this corner,another student sees two images of the wire,located symmetrically on each side of the line of sight. The separation (in $cm$) between these images is:

The wavelength of light diminishes $\mu$ times ($\mu = 1.33$ for water) in a medium. $A$ diver from inside water looks at an object whose natural colour is green. He sees the object as