Topic 1 - Magnification Flashcards
What is magnification
Is the degree to which the size of an image is larger than the image itself
What is resolution
Is the degree to which it is possible to distinguish between two objects that are very close together
Magnification formula
Image = object size X magnification
Overall magnification of light microscope =
Eyemagnification X objective magnifications
Conversions
centimetre to millimetre X10
Millimetre to centimetre /10
Millimetre to micrometer X1000
Micrometer to millimetre /1000
Micrometer to nanometer X1000
Nanometer to micrometer /1000
Light microscope
Thin specimen
Requires staining
Magnification limited to distance 0.5
Cells and large organelles viewed
Light optical magnification
Series of lenses through which ordinary white light can be focused
The total magnification is eyepiece magnification multiplied by the object magnification
The maximum magnification of the light microscope is X1500
Transmission electron microscope
Thin specimen
Users have a positive ions for staining
Beam of electrons
Small organelles ribosomes viewed
Scanning electron microscope
Beam of electrons hitting surface this 3-D image
Crystal clear resolution at high magnification
Light microscope advantages
Small and portable
Unaffected by magnetic field
Preparation of material quick and simple
Material really distorted by preparation
Natural colour of object observed
Cheap to purchase and operate
Electron microscope disadvantages
Very large uses and special rooms
Affected by magnetic field
Preparation of material lengthy requires experience
Preparation may distort material
Images are black and white
Expensive to purchase and hard to operate
