1. Behaviour of Light
Knowledge of fundamental properties of light and optics is essential to understand microscopy. The visible spectrum used in light microscopy forms a very small portion of the total electromagnetic radiations.
This small fraction of spectrum is of particular value, since the waves of electromagnetic spectum above and below the visible spectrum (400-700 nm) are not perceptible to an average human eye under the normal conditions.
This does not mean that other fractions of spectrum generates wavelength in the visible range; e.g. fluorescent screen in electron microscopy, photographic emulsions in ultra violet microscopy
