​A rainbow is formed by water droplets suspended in the atmosphere after the rain shower. The phenomenon responsible for occurring of rainbow consists of:​​

Correct option is A

Correct Answer: A

Explanation

• A rainbow is a natural spectrum appearing in the sky after a rain shower, caused by the dispersion of sunlight by tiny water droplets.
• When sunlight enters a water droplet, it first undergoes refraction (bending of light) and breaks into its constituent colors (dispersion).
• These colored rays then strike the back of the droplet and undergo internal reflection.
• Finally, the light is refracted again as it exits the droplet, reaching the observer's eye to form the arc of a rainbow.

Information Booster

• For a rainbow to be visible, the Sun must be behind the observer, as rainbows always form in the direction opposite to the Sun.
• The water droplets act as tiny prisms that both refract and disperse the incident sunlight.
• A Primary Rainbow involves one internal reflection, while a Secondary Rainbow is formed by two internal reflections.
• In a secondary rainbow, the order of colors is reversed (Violet is on the outer edge and Red is on the inner edge).

Additional Knowledge

• Option B (Reflection only): Simple reflection (like in a mirror) does not separate white light into its component colors; it would only show a reflected image of the source.
• Option C (Refraction only): While refraction is necessary to bend the light, it cannot account for the light returning toward the observer without the internal reflection step.
• Option D (Combination of refraction, scattering and dispersion): Scattering is the phenomenon where light is redirected in various directions by particles; it is responsible for the blue color of the sky but not the specific focused arc of a rainbow.