Compound Microscope :

Introduction

It is an optical instrument by which a small object can be seen very
much magnified.

Construction :

  It consists of two convex lenses fitted at ends of two tubes.One
of these two tube can move into the other to change the distance between the
lenses.The lens near the object has short focal length and it is called objective,
whereas; the lens near the eye has large focal length and it is called eye piece.
There is a mirror at the base which reflects light on object.

Working

1.The Object Is Placed Between 2f and f of the objective lens.
2.The objective lens produce a real inverted and magnified image beyond 2f.
3.This image comes within the focal length of the eye piece.
4.The eye piece acts as magnifying glass, producing a very enlarge image
which is virtual.

Simple Microscope :

  A simple microscope (magnifying glass) is simply a single
biconvex (converging lens of a short focal length.
The object to be seen as magnified is placed within the focal length of the lens.
This produces an enlarged, virtual and erect image towards the object itself.

Magnification Of Simple Microscope :

The magnification of a simple microscope is determine by;

M=1+ d/f
Where 'f' is the focal length of the lens and 'd' is te near point distance
of the object which is about 25cm for the normal eye.