The units of cell measurement are meter (M), decimeter (dm), centimeter (cm), millimeter (mm), micrometer or micron (µ), nanometer (nm) and angstrom (Å).
1 meter = 100 cm = 1000 mm = 1,000,000 micrometers = 1,000,000,000 nanometers
1 cm = 10 mm = 1/100 meter
1 mm = 1/10 cm = 1/1000 meter
1 micrometer = 1/10,000 cm = 1/1,000,000 meter
1 nanometer = 1/10,000,000 cm = 1/1,000,000,000 meter
1 nm = 0.001 µm = 10 Å
Cells larger than 100 μm are visible to the naked eye.
A light microscope can see from 0.2 μm to a maximum of 40 μm and a magnification of up to 2,000 times.
Electron microscopes can see from 0.5 μm to 20 μm at a maximum magnification of 500,000 times.
Electron microscopes use electron beams at shorter wavelengths. So many tiny objects are visible.