Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

Which microscope uses a beam of electrons to achieve high resolution images?

1. Light microscope

2. Scanning Electron Microscope (SEM)

3. Transmission Electron Microscope (TEM)

4. Compound microscope

The correct answer is: Scanning Electron Microscope (SEM)

The Scanning Electron Microscope (SEM) utilizes a beam of electrons to produce high-resolution images of the surface of a specimen. By scanning the surface with focused beams of electrons, the SEM generates detailed three-dimensional images, allowing scientists to observe fine surface details and texture that would not be visible with light-based microscopes. While the Transmission Electron Microscope (TEM) also uses electrons, it focuses on transmitting electrons through a thin specimen to create images, which is different from the surface imaging technique employed by SEM. In contrast, both the light microscope and compound microscope use visible light and lenses to magnify samples, significantly limiting their resolution compared to electron microscopy. Therefore, the unique operational principle of SEM is key to its ability to provide high-resolution images of specimen surfaces.