Question

define resolving power of compound microscope .how does the resolving power of a compound change when-a refractive index of medium between the object and objective lens increases b wavelength of the light used is increased c decreasing the diameter of objective d increasing the focal length of its objective

Answer 1

Resolving Power of Microscope:

For microscopes, the resolving power is the inverse of the distance between two objects that can be just resolved. This is given by the famous Abbe’s criterion given by Ernst Abbe in 1873 as

△ d = λ2 n sin θ

Resolving power = 1△ d = 2n sin θλ

Where n is the refractive index of the medium separating object and aperture. Note that to achieve high resolution n sin θ must be large. This is known as the Numerical aperture.