5 Questions
What does the instrumentation of SEM consist of?
Source, objective lens, and an electrode that deflects electrons.
What is the primary advantage of SEM over TEM?
SEM provides a 3D view of the specimen's surface.
What is the principle of SEM based on?
Scattering electrons and scanning the specimen based on its different depth of field.
How are electrons deflected in SEM?
A negatively charged anode deflects electrons to the objective lens.
What is the advantage of SEM in understanding materials like drugs and salt crystals?
SEM provides a crisp and detailed image with higher resolution.
Study Notes
Scanning Electron Microscopy (SEM)
- SEM instrumentation consists of an electron gun, scanning coils, detectors, and a vacuum system.
Advantage of SEM over TEM
- The primary advantage of SEM over TEM is its ability to image surfaces of samples, whereas TEM is limited to imaging thin sections.
Principle of SEM
- The principle of SEM is based on the scanning of a focused beam of electrons over a sample, which interacts with the sample, producing signals that contain information about the sample's surface topography.
Electron Deflection in SEM
- In SEM, electrons are deflected by electrostatic or magnetic fields to scan the sample in a raster pattern.
Advantage of SEM in Understanding Materials
- The advantage of SEM in understanding materials like drugs and salt crystals is that it allows for the study of their surface morphology, which is crucial in understanding their properties and behavior.
Test your knowledge of scanning electron microscopy (SEM) with this quiz. Explore the instrumentation and applications of SEM, and learn about its capabilities in visualizing 3D specimens at high resolution.
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