Which of the following statements about oil immersion in light microscopy is correct?

• A. Oil immersion is only used with the highest power objective lens to increase resolution.
• B. Oil immersion can be used at all magnification levels to increase resolution.
• C. Oil immersion is used to clean the lenses after observation.
• D. Oil immersion decreases the resolution of the microscope.

Answer: (A)

Verified step by step guidance

1. Understand the purpose of oil immersion in light microscopy: it is used to increase the resolution of the microscope by reducing light refraction between the specimen and the objective lens.
2. Recall that oil immersion is specifically applied with the highest power objective lens, typically the 100x objective, because at this magnification, the numerical aperture is high and light refraction can significantly reduce image clarity.
3. Recognize that oil immersion is not used at all magnification levels; lower power lenses do not require oil because their numerical apertures and working distances differ, and the oil would not improve resolution.
4. Note that oil immersion is not used for cleaning lenses; instead, it is a technique to improve image quality during observation.
5. Understand that oil immersion increases, rather than decreases, the resolution of the microscope by allowing more light to enter the objective lens, thus improving the detail visible in the image.