Question

The refractive indices of materials A, B, C and D are 1.52, 1.33, 1.71 and 2.42 respectively. The speed of light is maximum in

• A. A
• B. B
• C. C
• D. D

Answer 1

Answer: (B)

B

Answer is B.
The cause of refraction is a change in light speed; and wherever the light speed changes most, the refraction is greatest. The speed is related to the optical density of a material that is related to the index of refraction of a material. Air is the least dense material (lowest index of refraction value) and water is the denser material (largest index of refraction value). Thus, it would be reasonable that the most refraction occurs for the transmission of light across an air-water boundary.
Refractive index is the the ratio of the velocity of light in a vacuum to its velocity in a specified medium.
Here, the refractive index will be more for a more denser medium as the speed of light through a denser medium will be lesser.
Hence, the speed of light is maximum in the B.