Microscopes (1) Flashcards
What is the function of the diaphragm in a microscope?
It adjusts the amount of light passing through the stage opening to properly illuminate the specimen / increase contrast and resolution.
What is the equation for an image’s field of view?
(Low power FOV) x (low power mag)/(high power mag)
What is the equation for actual size under a microscope?
FOV / # of cells in field of view
What are the six distinct characteristics of a compound light microscope?
- Uses light rays as an illuminating source
- Specimen takes minutes to prepare
- Specimen can be living or dead
- Glass lenses
- Greatest resolving power produces image at 0.2 μm
- Cells and larger organelles become visible
What are the six distinct characteristics of an electron microscope?
- Uses electron beams as an illuminating source
- Specimen takes days to prepare
- Specimen must be dead
- Magnet lenses
- Greatest resolving power produces image at 0.001 μm (200x greater)
- Ultrastructure of cells becomes visible
What is the difference between a scanning electron microscope and a transmission electron microscope?
SEM creates an image by detecting reflected or knocked-off electrons, while TEM uses transmitted electrons (passing through the sample) to create an image.
