How can the resolving power of a microscope be increased?
The resolving power refers to the ability of a magnifying instrument to separate detail of two closely placed object. The resolving power of an instrument or lens may therefore, be defined as the smallest distance between the two objects which can be identified as separate images with aided eye. The minimum distance between the objects that reveals them as separate entities can be given by the abbreviation. Equation:
Lm = 0.61 λ /NA
In above question Lm represents – limit of resolution. The value 0.61 is derived from the computation of a number of complex trigonometric ratios. Numerical Aperture (NA) = n Sin α, where n, is the refractive index of the medium and Sin α is the sine of the half angle of light entering the objective lens from the specimen and λ. is the wave length of the light used to illuminate the object.
The resolving power is inversely related to the wavelength of light and Numerical Aperture (NA). So, to increase the resolving power of a microscope or to diminish Lm between the two-points to be resolved by the microscope, we often use light of shorter wave length or increase the numerical aperture of the lens.