Chapter 5 Microscopy (MICRO)

kylerigonan's version from 2016-03-01 08:25


Question Answer
What is magnification?Process of enlarging an object's apparent size and results when light or other radiation such as UV bends (refracts) as it travels through curved lens
What does magnifying ability (power) refer to?Ratio of the object's apparent size when viewed through the lens compared to how the object would appear to the naked eye at a distance of 25 cm.
What is the magnifying ability of a compound microscope?The product of the magnification power of the ocular (eyepiece) lens and the power of the objective lens.
What is resolution (resolving power)?Refers to a len's ability to distinguish between objects that are close together, allowing the lens to reveal fine detail.
What does it mean when a len's resolving power is better?You have the ability to see objects that are close together and distinguish too.
What does the len's resolving power depend on?1) wavelength of the light being passed through the lens 2) Numerical aperture of the lens 3) Quality of the lens
Definition of numerical aperture?The len's ability to gather light
Why is the numerical aperture partially dependent on the media?Because depending on the media will determine how much light is being passed through as it gets to the lens
What does a lower refractive index mean in terms of resolution?The lower refractive index means that it'll bend light more than glass and the resolving power will be decreased
Why is oil immersion used at times with 100x?Using OIL with a Refractive Index of 1.52 will bend light less
what is contrast?refers to the differences in color and light between the parts of an object or between at object and its background.
What is field of view (field)Area that can be viewed at one time through a given objective.
What is the function of the eyepiece or ocular?part you look through to see a specimen. Usually contains 10X
What is the function of the arm? connects the oculars to the rest of microscope.
What is the function of the nosepiece or turret?Holds the various objective lenses. The nosepiece revolves to allow the user to switch from lens to lens
function of objective(lens)used to magnify a specimen for examination . 4X, 10X, 40X, 100X
What does it mean when the objective of a microscope is par focal?The objectives are focused relative to each other. When an object is in focus in one objective, only minor adjustments will be needed to bring the object into focus with another objective
function of stage?platform where glass slide rests on. Stage has clips to secure the slide and controls to move it
function of condenserfocuses the light onto the specimen by raising and lowering to adjust amount of light passing through the specimen
function of iris diaphragmlocated on the condenser. Adjust amount of light passing through the specimen by opening and closing
function of coarse adjustment knobraises and lowers the stage in large increments to focus specimen quickly. Used on 4x and 10x
function of fine adjustment knobraises and lowers the stage in very small increments and used when focusing the 40x and 100x objectives
function of lamp or light sourceprovides the light that will pass through the specimen, allowing to view the specimen
function of rheostatallow the user to adjust the lamp's output. Increase rheostat to increase amount of light when going from lower to higher magnifications.
function of baseprovide a stable platform for the microscope.
what are the 3 controls that can be adjusted to determine the amount of light coming through the specimen?1) Iris diaphragm of condenser (open & shut) 2) condenser (raised or lowered) 3) rheostat
How can you measure a organism's size?Diameter of FOV / # of organisms that will fit across field