Correct Option
The correct option is (c).
Explanation
Dispersion of light is the phenomenon of splitting of a beam of white light into its constituent colours when it passes through a transparent medium, such as a glass prism. This occurs because different colours (wavelengths) of light travel at different speeds in the medium, leading to different angles of refraction.
Statement-wise Analysis
- Statement 1 is Incorrect. Dispersion refers to the separation or splitting of white light into its component colours (spectrum). The process of combining these colours back to form white light is known as recombination, which can be achieved by placing an inverted prism after the dispersing prism.
- Statement 2 is Correct. A triangular glass prism is the standard optical device used to demonstrate dispersion. When white light enters the prism, it refracts (bends). Since the refractive index of glass is different for different wavelengths, the colours bend by different amounts (violet bends the most, red the least), resulting in a spectrum.
- Statement 3 is Correct. Sunlight, which appears white, is a composite of seven visible colours: Violet, Indigo, Blue, Green, Yellow, Orange, and Red (often abbreviated as VIBGYOR). Isaac Newton proved this by passing sunlight through a prism.
Key Takeaway
Dispersion is the splitting of white light into its spectrum due to the dependence of the refractive index on the wavelength of light. Violet light has the shortest wavelength and deviates the most, while red light has the longest wavelength and deviates the least.