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If your specimen is too small to be seen with a light microscope you can use an electron microscope?
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∙ 12y ago
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∙ 12y ago
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Why are we not able to see viruses viruses with compound light microscopes we use is the science lab?
Becoz they r too smaller than bacteria and they examined in electron microscope(TEM&SEM)
How much magnification is needed to see a nanometer?
You cannot see down to the nanometer scale with light microscopes, you have to use something like a scanning tunneling microscope or an electron emission microscope. And since those don't use light I'm not sure you can really define the magnification.
Microscope is an indespensable tool why?
A microscope (literally ~ 'see small') is a device to aid our natural eyesight. A low power microscope (<40 times) is very useful in inspection of samples, and in dissecting small structures. Such as parts of a flower. Stereo microscopes are good in this region. From here you go up to medium power 'scopes, up to a few hundred times. You'll now be looking at the grains of sandstone and similar small items. A binocular microscope will be useful, but you'll no longer have stereo presentation. Much more than a few thousand becomes difficult for a light microscope, for your subjects themselves approach the wavelength of light in size. Beyond this, electron microscopes rule, and they may not actually look at the specimen directly. They fire a beam of electrons at the specimen, and display the results on a video screen. But you can have much more fun here, for if the electrons are sufficiently energetic, they can cause secondary emission from the sample, and analysing these emissions can identify the elements in the sample. You'll now be looking at part of an individual grain of a sandstone. And with an EM microscope it is simple to copy the picture from the video screen.
What is an advantage of using an electron microscope?
Answer: Using an EM (electron microscope) you can look INSIDE a cell and take photos. This is different to an ordinary (or Light microscope) where you generally only see the outside of the cells - or at best can only see vague shapes inside the cell. Answer: The scanning electron microscope provides a number of advantages over an optical microscope. Primarily this centers around the fact that the wave lengths used are much smaller than the wavelengths of light. What you can see is, in par,t dependent on the relative size of the object and wavelength of the light you are using. For very small objects, like individual atoms, light just wont work. Secondly the electron microscope can be fitted out with equipment and analytical sensors to identify the atomic composition of materials in the field of view. These Scanning Electron Microscopes (SEM) are extremely useful in identifying trace contaminants. The standard microscope still has advantages. It can detect the polarizing capacity of organic compounds, it is cheap and easy to use, it can be used in the analysis of stained samples in microbiology, it can use transmitted light and reflected light to examine an object. A major advantage is that the surface of the viewed object does not have to be prepared by being covered with a very thin layer of metal to permit viewing.
What are the other types of microscope?
Light (Optical) Microscope:Basically it acts as a two stage magnifying device. An objective lens provides the initial enlargement and an ocular lens is placed so as to magnify the primary image a second time. Total magnification is obtained by multiplying the magnifying power of the objective and ocular lenses. An additional condensing lens is normally employed beneath the stage of microscopes to concentrate the light from its source into a very bright beam illuminating the object, thus providing sufficient light for inspection of the magnified image.Polarizing Microscope:Many natural objects including crystals & fibers exhibit special optical property known as double refraction or birefringence. In histological material, birefringence is caused by asymmetric particles, too small to be resolved even by best possible lenses. The polarizing microscope is a conventional microscope in which a nickel prism or Polaroid sheet is interposed in the light path below the condenser. This "Polarizer" converts all the light passing through the instrument into plain polarized light (light which vibrates in one optical plane only). A similar second prism termed "analyzer" is placed within the barrel of the microscope above the objective lens. When the analyzer is rotated until its axis is perpendicular to that of polarizer, no light can pass through the ocular lens, resulting in a dark field effect. The field will remain black if an isotropic or singly refractive object is placed on the stage. A birefringent object, however, will appear bright upon a dark background when examined in this manner.Phase contrast Microscope:Lack of contrast has always been a problem in biological work because the refractive indices of cytoplasm and its inclusions are similar. In normal microscopy the problem is solved by staining differentially but this is subject to numerous limitations. Phase microscopy provides a method whereby contrast is created by purely optical means. Refractive index is the measure of optical density of an object or the speed with which it is traversed by the light wave. Air e.g. has a refractive index of approximately 1.0, Water 1.3 and a glass about 1.5. In other words, light traverses fastest in air, more slowly in water and slower still in glass.Interference Microscope:It depends upon the ability of an object to retard light. However, unlike the phase microscope, which depends upon the specimen diffracting light, the interference microscope send two separate beams of light through the specimens, which are then combined in the image plane. After recombination, difference in retardation of light results in interference that can be used to measure the thickness or refractive index of the object under investigation.Dark field Microscope:This microscope utilizes a strong, oblique light that does not enter the objective lens. A special dark field condenser, in which no light passes through the center of the lens, is employed. Light thus reaches the object to be viewed at an angle so oblique that none of it can enter the objective lens. The field is therefore dark. However small particles present in the specimen will reflect some light into the objective lens and will appear as glistening spots. Thus, it is possible to visualize particles far below the limits of bright light resolution. The effect is similar to phenomenon of dust particles seen in a beam of sunlight entering a darkened room.Ultraviolet Microscope:Since ordinary optical lenses are practically opaque to ultraviolet rays of light, quartz lenses are used throughout the lens system of this microscope.This microscope depends upon the differential absorption of ultraviolet light by molecules within the specimen and the results are recorded photographically. In principle, this system allows an improvement in resolution about twice that of light microscope. This system is useful for detecting proteins that contain certain amino acid and in detecting nucleic acids.Transmission Electron Microscope (TEM):The transmission electron microscope utilizes a system which in principle is analogous to that of light microscope. In electron microscope, the illuminating source is a beam of high velocity electrons, accelerated in vacuum. The beam is passed through the specimens and is focused upon a fluorescent screen or photographic plate by series of electromagnetic or electrostatic fields. The wave length of the electron depends upon the acceleration voltage used. At the voltage used routinely, the wavelength of electrons is of the order of 0.05 A° (Angstroms).Scanning Electron Microscope (SEM):It is a more recent development and unlike TEM, it does not depend upon electrons passing through the specimen under examination. The SEM bombards the surface of a specimen with a finely focused beam of electron. As the beam strikes a point on the specimen, deflected primary and emitted secondary electrons which originate from the surface are collected by a detector. The resulting signals are accumulated from many points to build up an image that is displayed on a cathode ray tube. Since the scanning electron microscope is characterized by a great depth of focus, it gives a three dimensional image of the surface of a bulky specimen. The electron microscopes (TEM and SEM) require special technique for preparing specimens for examination.
What two microscope are used to view very small organisms?
Two types of microscopes used to view very small organisms are the light microscope, which uses light to magnify the specimen, and the electron microscope, which uses a beam of electrons to create a highly detailed image of the specimen at a much higher magnification than a light microscope.
What does the electron microscope do?
An electron microscope uses a beam of electrons to illuminate a specimen, providing higher resolution images than a light microscope. It can magnify structures up to 2 million times, allowing for detailed examination of small objects at the molecular and atomic levels.
Advantages and disadvantages of light microscope over electron microscope?
Advantages of light microscope over electron microscope include lower cost, easier operation, and the ability to observe living specimens. Disadvantages include lower resolution, limited magnification, and inability to visualize structures at the atomic level like electron microscopes.
What do things that are to small for a light microscope get viewed by?
Things that are too small for a light microscope, such as viruses and molecules, can be viewed using an electron microscope. Electron microscopes use a beam of electrons instead of light to magnify objects at a much higher resolution than light microscopes.
Would you use a stereomicroscope or compound light microscope or electron microscope to see a virus?
You would typically use an electron microscope to see a virus, as viruses are much smaller than what can be resolved using a compound light microscope or stereomicroscope. Electron microscopes use a beam of electrons to create high-resolution images of small objects like viruses.
What type of microscope would you need to see detailed images of an internal structure of a bacterium a light microscope or an electron microscope?
An electron microscope would be needed to see detailed images of an internal structure of a bacterium, as it can provide much higher magnification and resolution compared to a light microscope. The electron microscope uses a beam of electrons instead of light to visualize the specimen, allowing for better visualization of internal structures at the cellular level.
How do light microscopes defer from electron microscopes?
electron microscopes can help you see very small small organisms. Unlike a light microscope A light microscope uses visible light, focussed by lenses. An electron microscope uses beams of electrons, focussed by magnetic coils. The electron microscope can indeed image smaller objects than an optical (light) microscope. Both can image objects smaller than can be seen with a magnifying glass.
What is the difference between a Light Microscopes and an Electron Microscope?
The optical microscope is the most common. It uses light to image a sample that is too small to be seen by the naked eye.The scanning electron microscope examines the surface of objects using an electron beam and measuring reflection.Short Answer = Resolution.
What two properties does a light microscope need to work?
A light microscope requires a light source to illuminate the specimen being observed, and lenses to magnify and focus the image. These properties allow for the visualization of small details in the specimen at a higher resolution.
Why does a microscope stage have a small hole in it?
The small hole in a microscope stage allows light to pass through to illuminate the specimen from below. This lighting technique is known as transmitted light microscopy and is essential for observing translucent or transparent samples.
What type of microscope would you use to view HIV?
You would need an electron microscope to view HIV because it is a virus and is too small to be observed with a light microscope. Electron microscopes use a beam of electrons to create high-resolution images of tiny objects like viruses.
What is the small platform where the specimen is mounted for examination on a microscope?
The small platform where the specimen is mounted for examination on a microscope is called a microscope slide. It is a thin, flat, usually rectangular piece of glass or plastic on which the specimen is placed for observation under the microscope.
