Question

The phenomenon of splitting of white light through prism into a band of colours is called :

• A. Dispersion of light
• B. Reflection of light
• C. Refraction of light
• D. Scattering of light

Hint:

Think of a rainbow. A prism does something similar to raindrops: it takes white light and "disperses" it, meaning it spreads it out into its individual colors (like red, orange, yellow, green, blue, violet). So, "Dispersion" is the key word for this color-splitting effect.

Answer 1

The Correct Option is A

Concept: When white light passes through a prism, it separates into its constituent colors. This phenomenon has a specific name. Step 1: Understanding the process White light (like sunlight) is actually a mixture of different colors of light (violet, indigo, blue, green, yellow, orange, red - VIBGYOR). Each color has a slightly different wavelength. When white light passes through a medium like a prism, these different colors bend by slightly different amounts due to differences in their speeds within the prism material. This causes them to separate. Step 2: Defining the terms in the options
(1) Dispersion of light: This is the phenomenon of splitting of white light into its component colors when it passes through a refractive medium (like a prism or a raindrop). This happens because the refractive index of the medium is different for different wavelengths (colors) of light.
(2) Reflection of light: This is the bouncing back of light when it strikes a surface. It does not involve splitting into colors in this context.
(3) Refraction of light: This is the bending of light as it passes from one medium to another. While refraction is necessary for dispersion to occur in a prism, dispersion is the specific term for the splitting of colors.
(4) Scattering of light: This is the process by which light is redirected in many directions when it encounters small particles or irregularities. Example: blue color of the sky. Step 3: Identifying the correct term The phenomenon described – splitting of white light into a band of colors (a spectrum) by a prism – is specifically called dispersion of light.