Question

Explain the phenomenon of dispersion of white light through a prism by making a diagram.

Hint:

The phenomenon of dispersion is responsible for the formation of rainbows, where sunlight is dispersed by water droplets in the atmosphere.

Answer 1

When white light passes through a prism, it is refracted (bent) due to the difference in refractive indices between air and the glass of the prism. The phenomenon of dispersion occurs because the different colors in white light have different wavelengths, and each color bends by a different amount. This causes the white light to spread out into its component colors, forming a spectrum.
Steps to draw the diagram:

Draw a triangular prism with one of its faces parallel to the horizontal axis.
Draw an incident beam of white light entering the prism at an angle to the surface.
The white light bends as it passes from air (lower refractive index) into the prism (higher refractive index). Each color bends by a different amount.
As the light exits the prism, it bends again, and the spectrum of colors (red, orange, yellow, green, blue, indigo, violet) separates more.
Diagram Description
Labeling the Diagram:


Incident Light: White light entering the prism.

Refracted Light: The light that bends inside the prism.

Colors of the Spectrum: The separate colors of light (red, orange, yellow, green, blue, indigo, violet) seen after the dispersion.

Explanation of Dispersion: - Red light bends the least because it has the longest wavelength. - Violet light bends the most because it has the shortest wavelength. - This difference in bending causes the white light to spread out into its component colors.