A rainbow is always seen in the part of the sky that is opposite to the Sun. Which one of the following corre…

Question

A rainbow is always seen in the part of the sky that is opposite to the Sun. Which one of the following correctly explains this?

(A) Sunlight must enter the water droplets from behind the observer so that internal reflection sends dispersed light back towards the observer's eyes.
(B) The atmosphere refracts sunlight downward, and only the region opposite the Sun is free of atmospheric interference.
(C) Water droplets on the side facing the Sun absorb light rather than dispersing it.
(D) Dispersion only occurs when light travels from a denser medium to a rarer medium, which happens only on the far side of the droplets.

Accepted Answer

## Model Answer **(A)** Sunlight must enter the water droplets from behind the observer so that internal reflection sends dispersed light back towards the observer's eyes. *Source: Chapter 10, Section 10.4 Dispersion of White Light by a Glass Prism* --- ## Explanation The textbook explicitly states: "A rainbow is always formed in a direction opposite to that of the Sun. The water droplets act like small prisms. They refract and disperse the incident sunlight, **then reflect it internally**, and finally refract it again when it comes out of the raindrop." This means the Sun must be **behind the observer** for internally reflected, dispersed light to travel back toward the observer's eyes — exactly what option (A) says. Options B, C, and D are scientifically incorrect and not supported by the passage.

Science (086) — AI-generated practice question