Laser is/are:

Properly arrange the effects with their reasons:

Effects	Reasons
$(i)$ Rainbow formation	$(a)$ Reflection
$(ii)$ Red colour of danger signals	$(b)$ Scattering
$(iii)$ Different colours of thin oil film and soap bubbles	$(c)$ Chromatic aberration
$(iv)$ Coloured images formed by lenses	$(d)$ Dispersion
$(v)$ Different colours of clouds	$(e)$ Interference

The difference in the number of wavelengths, when yellow light propagates through air and vacuum columns of the same thickness, is one. Find the thickness of the air column. Given: Refractive index of air $\mu_a = 1.0003$, Wavelength of yellow light in vacuum $\lambda_0 = 6000 \text{ Å}$.

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

Answer the following questions:
$(a)$ When a low flying aircraft passes overhead,we sometimes notice a slight shaking of the picture on our $TV$ screen. Suggest a possible explanation.
$(b)$ As you have learnt in the text,the principle of linear superposition of wave displacement is basic to understanding intensity distributions in diffraction and interference patterns. What is the justification of this principle?

Name some prominent scientists who have made significant contributions to the study of wave physics.