What is the equation for resolving power in microscopy?

The equation for resolving power in microscopy is correctly represented by the relationship involving wavelength and numerical apertures (N.A) of the condenser and objective lenses. In this context, resolving power refers to the ability of a microscope to distinguish between two close objects as separate entities. This ability is fundamentally influenced by the wavelength of light used and the numerical apertures of the optical components.

The resolving power improves when a shorter wavelength is used, and it also increases with higher numerical apertures, which correspond to the light-gathering ability and resolution capabilities of the lenses. The formula captures this by placing the wavelength in the numerator and the sum of the numerical apertures in the denominator. By combining the numerical apertures of both the condenser and the objective, we account for the total resolving capacity of the optical system, thus allowing for effective differentiation of fine detail in microscopic specimens.

The other options do not accurately reflect the relationship described by the established concepts of optics and microscopy, and they misuse mathematical operations or definitions regarding how resolving power is calculated in practical applications.