Why does immersion oil improve the resolution of a microscope?

• A. It increases the numerical aperture of the objective lens.
• B. It changes the wavelength of light used for illumination.
• C. It decreases the magnification of the microscope.
• D. It reduces the working distance between the lens and the specimen.

Answer: (A)

Verified step by step guidance

1. Understand the concept of resolution in microscopy: Resolution is the ability of a microscope to distinguish two close points as separate entities. Higher resolution means clearer and more detailed images.
2. Learn about numerical aperture: Numerical aperture (NA) is a measure of a microscope's ability to gather light and resolve fine specimen detail at a fixed object distance. It is influenced by the refractive index of the medium between the specimen and the objective lens.
3. Explore the role of immersion oil: Immersion oil has a refractive index similar to glass, which helps to minimize light refraction and loss as light passes from the specimen to the objective lens. This increases the numerical aperture.
4. Analyze how immersion oil improves resolution: By increasing the numerical aperture, immersion oil allows more light to enter the objective lens, enhancing the resolution and clarity of the image.
5. Consider the incorrect options: Immersion oil does not change the wavelength of light, decrease magnification, or reduce the working distance. Its primary function is to increase the numerical aperture, thereby improving resolution.