Physics
20
Dispersion
12
⚡ Quick Summary
Dispersion is the phenomenon where white light separates into its constituent colors when passing through a transparent medium like a prism. This happens because the refractive index of the material varies slightly with the wavelength of light. Different colors bend at different angles, with violet bending the most and red the least.
µ = µ₀ + A/λ²
- Dispersion: The phenomenon of separation of different constituent colours of light while passing through a transparent medium.
- The refractive index (µ) of a material depends on the wavelength (λ) of light.
- Cauchy's Equation (approximate): µ = µ₀ + A/λ², where A is Cauchy's constant.
- Refractive index decreases as wavelength increases.
- For visible light, refractive index is maximum for violet and minimum for red.
Dispersive Power
12
⚡ Quick Summary
Dispersive power quantifies how much a material separates different colors of light compared to the average deviation of light. It's the ratio of angular dispersion (difference in deviation between violet and red light) to the mean deviation (deviation of yellow light).
Dispersive Power = (δv - δr) / δ where δ is deviation of yellow light
- Angular Dispersion: The angular divergence of the transmitted beam (δv - δr), where δv and δr are the deviations for violet and red components, respectively.
- Mean deviation (δ) is conventionally measured by the deviation of yellow light.
- Dispersive power is the ratio of angular dispersion to the average deviation when a light beam is transmitted through a thin prism.