What is the resolving power of a light microscope?

The resolving power of a light microscope is fundamental to its ability to distinguish between two close objects. The correct value of 0.2 micrometers (or 200 nanometers) is derived from the physical principles governing light and optical systems. This resolution limit is largely a result of the wavelength of visible light; since the microscope uses light for imaging, it cannot resolve objects that are closer together than approximately half the wavelength of the light used. Given that visible light has wavelengths ranging from about 400 to 700 nanometers, a resolving power of around 0.2 micrometers is consistent with our understanding of how light interacts with small structures.

In contrast, other values indicate a much lower resolving power, which would not align with the capabilities of standard light microscopes. A resolving power of 0.5 micrometers would mean that objects closer than that could not be distinctly resolved, which underestimates the microscope's capability. Similarly, a value of 0.1 micrometers would surpass the natural limits of light microscopy under typical conditions, and 1 micrometer would imply a much less effective resolution. Understanding this concept is critical for microbology, as it dictates the smallest structures that can be observed and studied using light