- Dispersion occurs because the refractive index (n) of the medium depends on the wavelength (λ). - In most transparent materials (normal dispersion), refractive index decreases as wavelength increases (n_violet > n_blue > ... > n_red). - Deviation (δ) in a prism depends on the refractive index (for a small angle prism, δ ≈ (n-1)A). Higher n means greater deviation. - Speed of light in the medium (v) is inversely proportional to the refractive index (v = c/ n). Higher n means lower speed. - Thus, blue light has a higher refractive index, deviates the most, and has the lowest speed in the prism.
In the dispersion of white light by a common glass prism, which one among the following is correct ?
Asked in UPSC NDA 1 2023 · Topic: Optics (Prisms and Dispersion)
Show answer
Answer: D. Blue light deviates the most because blue light has lowest speed in prism
More Physics questions
- Which of the following statements with regard to the phenomenon of the primary rainbow formation by water droplets is/are correct ? 1. It involves refraction and one internal reflection of sunlight. 2. It involves refraction of sunlight only. 3. It is formed as the inner bow. 4. It may involve more than one internal reflection as well as refraction of sunlight. Select the answer using the code given below :
- A rainbow is produced due to which one of the following phenomena?
- Which one of the following figures correctly shows the path of a ray of light through a glass prism ?
- When a light beam falls on a triangular glass prism, a band of colours is obtained. Which one of the following statements is correct in this regard?
- The blue colour of water in the sea is due to:
- Which one of the following colours is least deviated by the glass prism ?
- Consider the following statements: Statement-I: Occasionally we see two rainbows together, the primary rainbow with another less intense secondary rainbow about 10 degrees away Statement-II: The secondary rainbow appears due to refraction after a reflection of sunlight from the water droplets Which one of the following is correct in respect of the above statements and the code?
- When a beam of white light is allowed to fall on a prism, the maximum deviation of the emerging light occurs for