The Human Eye & The Colourful World: Colour Spectrum
Explore the phenomenon of **dispersion of white light** to understand its constituent colors. This leads to a deeper appreciation of the **human eye's** ability to perceive a **colourful world** and how defects can be corrected.
Key Concepts and Phenomena
▼**White light** is composed of seven constituent colors (VIBGYOR). A **prism** causes dispersion because different colors of light travel at slightly different speeds through the glass, leading to different angles of refraction.
If the dispersed spectrum passes through an **inverted second prism**, the colors recombine to form white light again, demonstrating the composition of white light.
Phenomena like **twinkling of stars** and **advanced sunrise/delayed sunset** are caused by the refraction of light through Earth's atmosphere.
Experiment 1: The Colour Spectrum (Dispersion)
Simulate passing white light through a prism to observe its dispersion into constituent colors (VIBGYOR).
(VIBGYOR: Violet, Indigo, Blue, Green, Yellow, Orange, Red)
Experiment 2: Eye Defects & Wavelength Challenge
Complete the physics challenge or identify the corrective lens for the defect shown.
Common defects include Myopia (nearsightedness, corrected by **concave lens**) and Hypermetropia (farsightedness, corrected by **convex lens**). Presbyopia, another defect, is corrected using bifocal lenses.
Atmospheric Phenomena and Colour
The blue color of the sky and the reddish appearance of the sun at sunrise/sunset are due to the **scattering of light** by fine particles in the atmosphere. Blue light scatters more due to its shorter wavelength.
A **rainbow** is a natural spectrum appearing in the sky after rainfall. It is caused by **dispersion, internal reflection, and refraction** of sunlight by raindrops.
The ability of the eye's lens to adjust its focal length to focus objects at different distances on the retina is called the **power of accommodation**.
