Sir $C.V.$ Raman was awarded the Nobel Prize for his work connected with which of the following phenomena of radiation?

To an observer on the earth,the stars appear to twinkle. This can be ascribed to

Which radiation in sunlight causes a heating effect?

Blue colour of the sky is due to

Why does the Sun have an elliptical shape at the time of sunrise and sunset? It is due to:

Let $S_1$ be the amount of Rayleigh scattered light of wavelength $\lambda_1$ and $S_2$ that of light of wavelength $\lambda_2$ from a particle of size $a$. Which of the following statements is true?