https://www.digistore24.com/redir/365899/jobsget/

1. Assignment
#1
Assignment of Microbiology
Submitted to Sir Waqas
Submitted by Madiha
Submission
date
25 Dec,2021

2. MICROSCOPE
AND ITS TYPES

3. MICROSOPE
Definition :A piece of laboratory equipment that is used to magnify small things that are too small to be seen by the naked
eye , or too small for the details to be seen by the naked eye , so that their finer details can be seen and studied.
 Explanation :Magnifier of the image of small objects; the invention of the microscope led to the discovery of the cell . An
instrument that can be used to magnify the
size of an object for study purposes, and is the instrument that can be used to investigate Biological
matter more closely. A microscope is an instrument that is used to magnify small objects. ... It is
through the microscope's lenses that the image of an object can be magnified and observed in detail.
A simple light microscope manipulates how light enters the eye using a convex lens, where both sides
of the lens are curved outwards . Microscopes are generally made up of structural parts for holding and
supporting the microscope and its components and the optical parts which are used for magnification and
viewing of the specimen images. This description defines the parts of a microscope and the functions they perform to enable the
visualization of specimens.

4. Types of microscope
 There are many types of microscope .
 Light Microscopes
 Fluorescent Microscopes
 Electron Microscopes
 X-Ray Microscopes

5. Definition: An electron microscope is a microscope that uses a beam of accelerated
electrons as a source of illumination. It is a special type of microscope having a high
resolution of images, able to magnify objects in nanometres, which are formed by controlled
use of electrons in a vacuum captured on a phosphorescent screen.
Discovery : Ernst Ruska (1906-1988), a German engineer and academic professor,
built the first Electron Microscope in 1931, and the same principles behind his prototype still
govern modern EMs.
Explanation: The electron microscope uses a beam of electrons and their wave-
like characteristics to magnify an object's image, unlike the optical microscope that uses
visible light to magnify images. Conventional optical microscopes can magnify between 40 to
2000 times, but recently what are known as "super-resolution" light microscopes have been
developed that can magnify living biological cells up to 20,000 times or more. However, the
electron microscope can resolve features that are more than 1 million times smaller.
1-Electron microscope

6. Diagram
Working :Electron microscopes use signals arising from the interaction of an electron beam with
the sample to obtain information about structure, morphology, and composition.
1.The electron gun generates electrons.
2.Two sets of condenser lenses focus the electron beam on the specimen and then into a thin tight beam.
3.To move electrons down the column, an accelerating voltage (mostly between 100 kV-1000 kV) is applied
between the tungsten filament and anode.
4.The specimen to be examined is made extremely thin, at least 200 times thinner than those used in the
optical microscope. Ultra-thin sections of 20-100 nm are cut which is already placed on the specimen holder.
5.The electronic beam passes through the specimen and electrons are scattered depending upon the thickness

7. Definition :A light microscope is a biology laboratory instrument tool,
that uses visible light to detect and magnify very small objects and enlarge
them.
They use lenses to focus light on the specimen, magnifying it thus producing an
image. The specimen is normally placed close to the microscopic lens.
Explanation:Microscopic magnification varies greatly depending on
the types and number of lenses that make up the microscope. Depending on the
number of lenses, there are two types of microscopes i. e Simple light
microscope (it has low magnification because it uses a single lens) and the
Compound light microscope (it has a higher magnification compared to the
simple microscope because it uses at least two sets of lenses, an objective lens,
and an eyepiece). The lenses are aligned in that, they can be able to bend light
for efficient magnification of the image.
2-Light microscope

8. Diagram
Principle: light microscopes visualize an image by using a glass lens, and magnification is
determined by, the lens’s ability to bend light and focus it on the specimen, which forms an image.
When a ray of light passes through one medium into another, the ray bends at the interface
causing refraction. The bending of light is determined by the refractive index, which is a measure
of how great a substance slows the speed of light. The direction and magnitude of the bending of
the light are determined by the refractive indexes of the two mediums that form the interface.