Final answer:
The Transmission Electron Microscope (TEM) is the type of electron microscope that uses electron beams passing through a thinly sliced specimen. It can visualize details as small as 0.1 nm and has allowed us to observe individual atoms and the structure of cell nuclei.
Step-by-step explanation:
The type of electron microscope in which streams of electrons are passed through a very thinly sliced specimen is the Transmission Electron Microscope (TEM). In the TEM, electrons are emitted from a hot filament and accelerated to pass through the sample. The electrons then form an image on a fluorescent screen or photographic plate, allowing us to see details as small as 0.1 nm. This microscope has been instrumental in visualizing individual atoms and the structure of cell nuclei.
An electron microscope is a type of microscope that uses electrons instead of light to illuminate the specimen and create an image. Electron microscopes have much higher resolution than light microscopes, allowing scientists to observe very small objects in great detail. There are two main types of electron microscopes: transmission electron microscopes (TEM) and scanning electron microscopes (SEM).
Transmission Electron Microscope (TEM):
In TEM, a beam of electrons is transmitted through an ultrathin specimen.
Electromagnetic lenses focus the electrons to form an image on a fluorescent screen or a digital detector.
TEM provides extremely high resolution, allowing scientists to see details at the nanoscale.
It is commonly used for studying the internal structure of cells, viruses, and other nanoscale materials.
Scanning Electron Microscope (SEM):
In SEM, a focused beam of electrons scans the surface of a specimen, and the resulting secondary electrons are detected to create an image.
SEM provides a three-dimensional surface view of the specimen.
It is particularly useful for studying the surface morphology of materials and biological specimens.
Key features and considerations of electron microscopes:
Resolution: Electron microscopes have much higher resolution compared to optical microscopes due to the shorter wavelength of electrons.
Magnification: Electron microscopes can achieve much higher magnifications, allowing the observation of structures at the atomic and molecular levels.
Specimen Preparation: Specimens for electron microscopy need to be very thin because electrons can penetrate only a short distance. This often involves complex preparation techniques like fixation, dehydration, and embedding in resin.
Vacuum: Electron microscopes operate in a vacuum to prevent electrons from scattering as they travel through the specimen.
Electron microscopes play a crucial role in various scientific fields, including biology, materials science, nanotechnology, and physics. They have significantly advanced our understanding of the microscopic world and continue to be indispensable tools in scientific research.