Simple microscope Class 12, Definition, Magnification, working, Parts And Uses

Knowledge Increases By Sharing...

Simple Microscope class 12

What is a simple microscope?

Definition: A simple microscope is used to view the magnified image of an object. It is made up of a convex lens. The convex lens produces a virtual, erect, and magnified image when the position of the object is within the focal length.

Simple microscope
Figure: This is the labeled diagram of a simple microscope showing its different parts source credit:

Main parts of the simple microscope

  • Eyepiece: This is the lens through which the observer views the image. It is generally positioned at the top.
  • Base: It is the bottom part of the microscope, and holds the structure.
  • Objective lens: This lens magnifies the object and forms the image.
  • Diaphragm: This will control the amount of light that falls on the object.
  • Stage: It is the platform used for placing the slides with samples.
  • Stage clip: These are used to hold the slides in the proper place.
  • Coarse adjustment knob: It is used to focus on scanning.
  • Fine adjustment knob: It is used to focus on oil.
  • Arm: It is used to support the tube and connects to the base of the microscope.
  • Power switch: The main power switch is used to turn on or off the microscope.
  • Condenser: It is used to focus the light on the sample and 400X power lenses are used

Working of the simple microscope

Simple microscope Class 12, Definition, Magnification, working, Parts And Uses
Figure: This figure illustrates how a simple microscope magnifies the object. Source credit: Pinterest

Working: The object is placed within the focal length of the lens, that is between the focus and the center of the lens. The emanating rays from the object appear to meet in the backward direction and hence form a virtual image of the object. The image so formed, is large in size, erect, and virtual.

Magnification of the simple microscope

The magnifying power of a simple microscope is given by the equation:

$$M = 1 + \frac{D}{F}$$

D: The shortest distance of distinct vision ( this is usually equal to 25 cm).

F: Focal length of the convex lens.

Uses Of Simple Microscope

  • It is used in pedology (a study of soil particles)
  • It is used by a dermatologist to find out various skin diseases.
  • It is used in microbiology to study samples of algae, fungi, etc
  • It is used by the jewelers to get a magnified view of the fine arts of the jewelry.


Ques: Find the magnifying power of a simple microscope, the focal length of the objective lens is 5 cm.


D = 25 cm, F = 50 cm

M=1 + D/F, so M= 1 + 25/5 =6

hence, the magnifying power of the lens is 6.


A simple microscope is a device used to magnify an object. Its magnification power is up to 10 times the object size. It can be used for basic purposes, but for a higher degree of magnification a Compound microscope is used.

Stay tuned with Laws Of Nature for more useful and interesting content.

Was this article helpful?
Knowledge Increases By Sharing...

Newsletter Updates

Enter your email address below and subscribe to our newsletter

0 0 votes
Rate this Article
Notify of

Inline Feedbacks
View all comments
Would love your thoughts, please comment.x