Question

If immersion oil was replaced with water, what would happen?

1) The refractive index would increase, improving resolution
2) The refractive index of water would be greater than air but less than oil, improving resolution less than oil.
3) The refractive index of water would be less than that of air, decreasing resolution.
4) There would be no difference.

Answer 1

Using water instead of immersion oil in microscopy would result in less resolution improvement than oil, but better than air, due to water's intermediate refractive index.

Step-by-step explanation:

If immersion oil was replaced with water, the correct outcome would be that the refractive index of water would be greater than air but less than oil, which would improve resolution less than oil. Specifically, water has a refractive index (n = 1.33) which is higher than that of air but lower than that of oil (n = 1.51). Immersion oil is used in microscopy between the cover glass and the objective lens because its refractive index is very close to that of glass, minimizing refraction and allowing more light rays to enter the objective lens. This maximizes the amount of light and thus improves the resolution of the image. When water is used instead of oil, there is more refraction compared to oil, but still less than air, indicating that resolution would be compromised, but not as much as with air alone.