Question

Resolving power of light microscope is
Option A- $0.2\mu m$ or $0.002mm$
Option B- $2\mu m$ or $0.02mm$
Option C- $0.02\mu m$ or $0.0002mm$
Option D- $100\mu m$ or $0.1mm$

Answer 1

Light microscope is a microscope which commonly uses visible light and a set of lenses for the magnified images of small objects. It is also known as an optical microscope. These microscopes are of two types: simple and compound microscopes.

Complete answer:
Different types of microscope have different resolving powers. Resolving power of a microscope is the ability of an optical instrument to distinguish small adjacent images. Light microscopes are extremely versatile instruments. We can use them to examine a wide variety of specimens like of any size, whole or sectioned, living or dead, wet or dry, hot or cold, and static or fast moving.

Option A-$0.2\mu m$ or $0.002mm$-When we use an objective lens of NA 1.4, with green light of wavelength 500nm, the resolution limit is $0.2\mu m$: The greater is the resolving power, the distance between two lines is minimum and the larger the NA (numerical aperture) higher is the resolving power.
Option B- $2\mu m$ or $0.02mm$: it is not the correct option because it is not the resolving power of a light microscope.
Option C- $0.02\mu m$ or $0.0002mm$: it is not the correct answer because again resolving power given is not correct.
Option D- $100\mu m$ or $0.1mm$: Not correct option because resolving power of light microscope is not $100\mu m$.

So, our correct answer is Option A.

Note:
Magnification of light microscope-A varying range of objective lenses with different magnification are usually used for viewing the object. These allow them to be rotated into place and provide ability to zoom the object and see it. The maximum magnification power of light microscopes is basically limited to around 1000x due to limited resolving power of visible light. The magnification of a compound light microscope is the product of the magnification of the eyepiece (say 10x) and the objective lens (say 100x), to give a total magnification of 1,000x.