Question

Rainbow is due to:

• A. Refraction and reflection of sunlight by water droplets
• B. Absorption of sunlight in minute water droplets
• C. Diffusion of sunlight through water droplets
• D. Ionization of water deposits

Hint:

Follow how sunlight bends on entering a droplet, reflects inside it, and bends again on leaving.

Answer 1

The Correct Option is A

Step 1: A rainbow forms when sunlight strikes tiny spherical water droplets suspended in the air after rain.

Step 2: As sunlight enters a droplet, it refracts, or bends, at the curved surface. Different colours of light bend by slightly different amounts, violet bends the most and red the least, so the white sunlight splits into its spectrum of colours, a process called dispersion.

Step 3: Inside the droplet, this dispersed light strikes the back surface of the droplet and undergoes total internal reflection, bouncing back roughly toward the direction it came from.

Step 4: The light then refracts a second time as it exits the front surface of the droplet, spreading the colours out further and sending them toward the observer's eye at slightly different angles for each colour, which is why we see distinct bands of red, orange, yellow, green, blue, indigo and violet.

Step 5: So a rainbow is produced by refraction, with dispersion, together with internal reflection inside water droplets, matching option A.