1.1.5: Microscopy
Not started yet — this one needs some love.
Magnification: how many times larger the image is than the real object.
Resolution: the ability to distinguish two separate points — higher resolution = finer detail.
Light microscope:
uses visible light
maximum magnification ~×2000; resolution ~200 nm
Electron microscope:
uses electrons → much higher magnification (up to ×500,000) and resolution
reveals sub-cellular structures (e.g. ribosomes) in far greater detail, which has improved our understanding of cells
Magnification formula (M = I ÷ R):
magnification = image size ÷ real size
real size = image size ÷ magnification
image size = magnification × real size
Unit conversions: 1 m = 10⁶ µm; 1 mm = 1000 µm; 1 µm = 1000 nm.
Common exam mistakes
Magnification ≠ resolution — a higher magnification without higher resolution just produces a bigger blurry image; electron microscopes have both higher resolution AND higher magnification.
The magnification formula has image size on top: magnification = image ÷ real. Writing it upside down (real ÷ image) is a frequent error.
Writing the formula as a triangle diagram alone is not creditworthy — you must state the equation in words or show it applied to values in a calculation.
Unit conversion: to convert mm → µm, multiply by 1000 (not divide); µm → nm, multiply by 1000. Many students divide when they should multiply.
Confusing metric prefixes causes calculation errors: micro (µ) = 10⁻⁶, nano (n) = 10⁻⁹, milli (m) = 10⁻³
'Seeing finer detail' and 'seeing more sub-cellular structures' are the same consequence of higher resolution, not two independent marking points — do not list them as separate answers.