Question

Short note on PRINCIPLES OF MICROSCOPY

Answer 1

Microscopes make small objects appear bigger. A light microscope will magnify an image up to 1500 times its original size. Electron microscopes can achieve magnifications up to 1million times. However, bigger is only better when more details are revealed. The fineness of detail that a microscope can reveal is its resolving power. This is defined as the smallest distance that two objects can approach one another yet still be recognized as being separate. Theresolution that a microscope achieves is mainly a function of the wavelength of the illuminationsourceitemploys.Thesmallerthewavelength,thesmallertheobjectthatwillcause diffraction, and the better the resolving power. The light microscope, because it uses visible light of wavelength around 500 nanometers (nm, where 1000 nm = 1 µm), can distinguish objects as small as about half this: 250 nm. It can therefore be used to visualize the smallest cells and the major intracellular structures or organelles. The microscopic study of cell structure organization is knownascytology.Anelectronmicroscopeisrequiredtorevealthe ultrastructure (the fine detail) of the organelles and other cytoplasmic structures

Answer 2

Microscopy is the technical field of using microscopes to view objects and areas of objects that cannot be seen with the naked eye (objects that are not within the resolution range of the normal eye).
There are three well-known branches of microscopy: 
optical, electron, and scanning probe microscopy.
Optical microscopy and electron microscopy involve the diffraction, reflection, or refractionof electromagnetic radiation/electron beams interacting with the specimen, and the collection of the scattered radiation or another signal in order to create an image. This process may be carried out by wide-field irradiation of the sample (for example standard light microscopy and transmission electron microscopy) or by scanning a fine beam over the sample (for example confocal laser scanning microscopy and scanning electron microscopy). Scanning probe microscopy involves the interaction of a scanning probe with the surface of the object of interest. The development of microscopy revolutionized biology, gave rise to the field of histology and so remains an essential technique in the life and physical sciences.