Question

Monochromatic light of wavelength 6000 Å incidents on a small angled prism. If the angle of the prism is 6°, the refractive indices of the material of the prism for violet and red lights are respectively 1.52 and 1.48, then the angle of dispersion produced for this incident light is

• A. 30°
• B. 36°
• C. 0.24°
• D. 0°

Hint:

In physics problems, if your calculated answer is physically reasonable but differs from the options by a factor of 10, 100, etc., double-check for a decimal point error in the options. Here, \(6 \times 0.04\) is clearly 0.24, making 24° a very likely typo.

Answer 1

The Correct Option is C

Step 1: Understanding the Question: The question asks for the "angle of dispersion produced for this incident light". "This incident light" refers to "Monochromatic light of wavelength 6000 A". 
Step 2: Concept of Dispersion: Dispersion is the splitting of polychromatic (white) light into its constituent colors because refractive index depends on wavelength. However, the incident light here is monochromatic (single wavelength). A single wavelength cannot be split into components. It will only undergo deviation. 
Step 3: Conclusion: Since there is only one wavelength, there is no separation of colors. Hence, the angle of dispersion (angular separation between extreme colors) is zero. Note: The provided refractive indices for violet and red are distractors, relevant only if the light were white.