Microscopes

Description

A-Level Biology (Cell Structure) Flashcards on Microscopes, created by Nazmin Shafiq on 26/11/2016.
Nazmin Shafiq
Flashcards by Nazmin Shafiq, updated more than 1 year ago
Nazmin Shafiq
Created by Nazmin Shafiq over 7 years ago
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Resource summary

Question Answer
Resolution Ability to differentiate between 2 close objects
Magnification How big an image is compared to the object
Equation for magnification
Decribe optical microscope Light focused by lens Light passed through specimen More light absorbed = darker Mag = Eyepiece x Objective lens
Advantages of optical microscope Cheap Easy to use True colour (may req staining)
Limits of optical microscope Low resolution (0.2um) Low magnification (1500x)
Decribe SEMs Directs beam of e- across specimen Image based on e- reflected ( Knocks of e- from spec Gather in cathode ray tube form image on comp ) ADDITIONAL
Advantages of SEMs High resolution (200,000x) Surface structure 3D High magnification (2nm) Thick spec
Limits of SEMs Lower resolution than TEM Dead spec Expensive Training B&W / False colour
Decribe Transmission Electron Microscope Use electomagnets to focus beam on e- transmitted through spec image based on e- absorbed Denser spec = more e- absorp = darker
Advantages of TEMs High resolution (2nm) images on internal structures High magnification (500,000x)
Limits of TEMs Thin spec Dead spec Expensive Training B&W / False colour
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