Microscopy Flashcards
Refraction
The bending and transmission of light waves through different mediums; calculated by velocity of light/velocity of light in transmitting medium.
focal point
the point through which all parallel rays of light will pass after passing through each part of the lens.
focal length
the distance from the center of the lens to the focal point.
what is a real image?
an image formed when an object is placed outside the focal point. It is inverted, can be projected onto a screen and differs in size form the object.
what is a virtual image?
an image formed when an object is placed inside the focal point. The image is not inverted and cannot be projected onto a screen.
What is the formula for resolution?
d = 0.61theta/n sin alpha; d should be small in order to have a greater resolution. n = refractive index.
What is resolution
the ability of a microscope to distinguish two small points as separate. Light microscope = 0.5 micrometers.
What is a light microscope?
A microscope that uses a series of lenses and light; is a descendant of microscopes from the 1800s.
What are the pros and cons of a light microscope?
It maginifies and resolves well, but the speciment must be thin and there is little contrast.
What is a phase contrast microscope?
converts phase shifts (invisible) passing through a specifmen into brightness changes (visible). Is used for living cells.
What is a fluorescent microscope?
Microscope that detects molecules that emit light of wavelengths in the visible range, as well as naturally occurring fluorescent molecules. Is used to detect induced fluorescence in antibodies and tracers.
What is a confocal scanning microscope?
Microscope that uses pinhole beams of light and constructs three dimensional images.
What are the pros and cons of a confocal scanning microscope?
It has high resolution, thin optical images are created, 3D reconstructions can be created.
What is a transmission electron microscope?
Microscope that uses a beam of electrons rather than light. It also uses potential differences between cathodes and anodes.
