microscopy Flashcards
Who created the microscope that allowed you to see bacteria?
Leeuwenhoek
what magnification was the microscope Leeuwenhoek made?
300x
What are the two main functions of the microscope?
magnification and resolution
What is the ocular lens responsible for?
inverts what you are seeing
What is the parfocal responsible for?
ensures you don’t have to adjust your focus when switching between objectives
how many lenses are there on a microscope? what are they?
2, objective lense, ocular lense
what are the 4 objectives lenses?
4x, 10x, 40x, 100x
what magnification does the ocular lens have?
10x
how do you determine total magnification?
objective lens x ocular lens
what is resolution?
defined as the ability to distinguish two adjacent objects as distinct and separate
Resolution was mathematically done by whom? when?
ernst abbe, 1870’s
what are the two things resolution depends on?
physical property of light (wavelength) and numerical aperture
what does numerical aperture (NA) refer to?
light gathering capabilities of a lens
what is the equation for resolution?
R= 0.61λ / NA
how do you enhance resolution?
you have a better image when R is small
how do you make R small?
decreased the wavelength of light used and increase numerical aperture
what is the equation of numerical aperture?
NA= n x sin(theta)
why can you see better on 40x and 100x objectives?
they allow for more light so you can see your image more clearly
As you move through objectives you are increasing ________ and thus enhancing the ________ through the ocular.
numerical aperture, resolution
what is the 100x referred to as?
oil emergent objective
why does oil help enhance the image?
because oil has a higher refractor index of 1.5 than opposed to air 1.0
why doe you start with the 4x objective when looking at a sample?
it has the widest field of view
how is dark field microscopy different?
uses the opaque light stop, and uses a dark background
T/F you cannot use staining procedures when using dark field microscopy.
true