For which pair among the following, the refractive index will have the minimum and maximum value, respectively?

Vacuum, diamond

The correct answer is Option (1) → Vacuum, diamond

The refractive index is minimum for the medium in which light travels fastest and maximum for the medium in which light travels slowest.

Among the given materials:

Vacuum → $n = 1$ (minimum)

Diamond → $n \approx 2.42$ (maximum)

Hence, the pair with minimum and maximum refractive index respectively is:

Answer: Vacuum, diamond