Page 1 : Practical ....., , EXPERIMENT 1, , To study the parts of a compound microscope., , THEORY/ PRINCIPLE, , =, , A, , Microscope is an extensively used instrument in a biological laboratory. It magnifies and resolves the, , image of the object seen through it using combination of various lenses, , A compound microscope is a complex assemblage or combination of different lenses that enable, highly magnified image formation of the microscopic biological objects (e.g. cells, tissues) and help in, studying the intricate details of cells and tissues. Compound microscope uses natural light to magnify, , and resolve the image of the object., , Working of a Microscope, i. Magnification, , The ratio of increased image to that formed on retina of an unaided normal eye is termed as, , magnification of the mircoscope. 5X, 10X or 40X indicates the strength of magnification., , Magnification of compound mircoscope = Magniiying power of objective lens x Magnifying, power of eye piece of ocular lens,, , e.g. a 5X eye piece and a 40X objective will magnify the image 5 x 40 = 200 times., , In general, in a compound microscope eye piece lens are 10X or 15X and objective lens are 10X as, , well as 40X, ji, Besolving Power, , points are possible. The formula for obtaining the resolving power of microscope is A = —*—, , 2NA, where, 4 = wavelength of light source, NA = numerical aperture, , Since, numerical aperture is negligible, it can be ignored., 5 Resolving power (R) = 2 / 2., 2. of visible light = 4000-7000 A., , , , If'we take thé average as 6000 A, the resolving power = “ = 3000A, , Therefore, the resolving power of a light compound microscope = 0.30 p or 3000 A or 300 nm., , compound microscope, muslin cloth, lens cleaning fluid and lens cleaning paper., , — Place the microscope on the working table., , a, , Resolution is the minimum distance at which distinction of two closed points as two separate, , , , Laboratory Manual BIOLOGY Ciass |

Page 2 : or silk cloth, 2.-Remove dust by wiping the microscope with the help of mu: F : ’ ee, 3.-Clean the lenses with the help of lens cleaning fluid and lens cleaning paper, , , Aldentify the various Parts of the microscope and draw a well labelled diagram of mien, labelling its various, , 5. Take a permanent slide or temporary slide prepared by you.and keep it on the Stage, fix, after focussing and view., , 6. Learn to use the Microscope by adjusting the focus, by moving the coarse adjustment, adjustment knobs., , osc, , , , , , OBSERVATION, Compound microscope has following two types of Parts:, L, | MECHANICAL PARTS, Base or foot, : allic structure that si, see ofthe base ‘uPPorts the microscope., Arm, d part of Mier, die ICrOscope and is useq oh Ni re th, ferent angles on the inclinay andling th, Inclination joint The arm, Stage, Stage clips, Diaphragm, Condenser, , tube heag

Page 3 : Eyepiece, , Revolving nosepiece — Body tube, , High power objective lens, , Coarse adjustment screw, Low power objective lens _, , Stage — Fine adjustment screw, , Clip —, Iris diaphragm, Condensor —, , Mirror, , Pilar, , Fig. 11 A compound microscope, , Eye piece lens This lens is fitted at the top of the body tube through which the magnified image of, or ocular lens the object can be seen. It has the magnification of 10X or 15X., , we, , rking of Microscope, 1. Themirroris adjusted in diffused source of light so that sufficient light enters into the microscope., , 2. The light entering into the microscope should be regulated to minimum by the help of diaphragm, and adjustment screws., , 3, Keep a clean prepared slide on the centre of the stage such that it lies just under the objective lens, and completely illuminated by diaphragm., , 4, Locate the object and focus it under low power objective by using coarse adjustment screw. For, obtaining the higher magnification turn the nose piece to next higher power by using fine, adjustment screw., , 5. The higher power objective should be used only when object is properly mounted under, cover-slip., , Experiment -2, , Laboratory Manual BIOLOGY Class 11th