Magnification Flashcards
Know the 2 formulas for calculating magnification Know the type and function of the 3 main types of microscopes Know about the electron microscope.
what is the formula for total magnification?
magnification of eyepiece / magnification of objective lens
what is meant by total magnification?
total magnification used by both lens to view an image.
what is the formula for the magnification of an image?
Size of image / size of real object
Why must textbooks show the magnification of the image?
To be more meaningful.
what is the highest magnification a light microscope ca go?
x1500
Why?
due to the ability of the microscope and short working distances of high power lenses
Does using a high power lens always guarantee more detail?
No as the detail of the image depends on the power and resolution which is basically the ability to distinguish between two points - whether you see them as 1 or 2.
What is the resolving power of a light microscope?
0.2μm or 200nm
what does this mean?
that you cannot pick out 2 points closer than 200nm apart.
What is an electron microscope used for?
looking at extremely thin sections of cells
what is the highest magnification an electron microscope can do?
x 1, 000, 000
what is the name of an electron microscope?
SEM, Scanning Electron Microscope
How does an SEM work?
Bounces electrons off the surface of the specimen which has an ultra thin coating of heavy metal, usually gold applied. A narrow electron beam scans the specimen and images formed are from the scattered electrons.
What do SEM’s reveal?
surface shape of structures such as small organisms and cells.
What does TEM stand for?
Transmission Electron Microscope
