A scientist is observing a bacteria through a compound microscope. For better analysis and to improve its resolving power he should. (Select the best option)

Solution

Physics sir · 3 steps

Resolving power depends on n sin θ over λ, so put oil between the slide and the objective.

1. What resolving power means. Resolving power is the ability to show two very close points as separate. The smaller the least distance d the microscope can resolve, the higher its resolving power.

   RP = 1/d = (2n sin θ)/(1.22 λ)

2. Read the formula. Here n is the refractive index of the medium between the object and the objective, θ is the half-angle of the cone of light the objective collects, and λ is the wavelength. The power rises with n and sin θ, and falls as λ rises.

   Option	Effect	Resolving power
   (a) Shorter eyepiece focal length	Raises magnification only	unchanged
   (b) Longer wavelength	λ goes up	decreases
   (c) Higher refractive index medium	n goes up	increases
   (d) Smaller objective diameter	θ goes down	decreases

3. So. Filling the gap with a high refractive index medium, such as cedar oil in an oil-immersion objective, improves the resolving power. The answer is (c).

The idea to keep. Magnification makes an image bigger. Resolution makes it sharper. For a microscope, resolving power grows with n sin θ and falls with λ, and the eyepiece plays no part in it.

Answer from the NTA final answer key. Solution by PrepWiser.