Silver artefacts get tarnished in air due to the formation of

The phenomenon of rainbow formation by water droplets involves :

The twinkling of a star is due to :

The red colour of the Sun at sunset and sunrise is due to –

The formation of glittering colours in thin foam of soap is the result of which of the following phenomenon –

Raman effect is due to Sir C. V. Raman. Which of the following statements is correct about 'Raman effect?