Microscopy Optical phenomenon used in microscopy are: Refection (change in direction of awavefrontat aninterfacebetween two diferentmediaso that the wavefront returns into the medium from which it originated) Difraction (hange in the directions and intensities of a group of waves after passing by an obstacle or through an aperture whose si!e is appro"imately the same as the wavelength of the waves) Refraction (change in direction of propagation of awavedue to a change in itstransmission medium) #right $eld% dar& $eld% phase contrast% fuorescence microscope' Resolution:Resolution is the ability of a lens to separate or distinguish between small ob(ects that are close together')he minimum distance (d) between two ob(ects that reveals them as separate entities is given by the *bbe e+uation% in which lambda (,) is the wavelength of light used to illuminate the specimen and n sin-is the numerical aperture (.*)'/a" value of sin - is 0 (12o ) Dar& 3ield /icroscopyObserving live ob(ects 4hase ontrast /icroscopy * phase5contrast microscope converts slight diferences in refractive inde" and cell density into easily detected variations in light intensity 4hase5contrast microscopy is used for 6tudying microbial motility Determining the shape of living cells Detecting bacterial components