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Diagram:, , N — screw head, , p= Pitch Scale, , D —Head Scale, (Circular Scale), , OM - Sagitta, , , , Observation:, , , , ; Distance moved on the pitch scale, Bie Number of complete rotations given to the screw head, , , , Pitch = Sty ee ee mm, , Total number of divisions on the head scale =............+, , Pitch, , Laat aoa = oe ee ee, east C Total number of head scale divisions, , ee ee dag mm, , KSPUPTF, , 26, , Na, , Experiment No. 3 bo: eee oo ere, SPHEROMETER, Aim: To determine the radius of curvature of a given spherical surface by, using a spherometer., Apparatus: Spherometer, watchglass, plane glass plate., , Principle: The linear distance moved by the screw is directly proportional to the, amount of rotation given to the screw head., , Formula: Do Pitch Distance moved on the pitch scale, ; itch = —— sss ee hn, ) Number of complete rotations given to the screw head, , Pitch, , t s SS ——, 2) Least Count, 22 Total number of head scale divisions , 3) Total Reading, TR= PSR+ (HSR x LC), Where PSR - Pitch scale reading, HSR - Head scale reading, 4) Radius of curvature, R = e = é, 6h 2, Where I — Mean distance between any two legs of spherometer., h— Value of Sagitta = hy — hy, h,. - Reading of the spherometer corresponding to, spherical surface., , hy - Reading of the spherometer corresponding to plane, , glass surface., , Procedure:, , 1) A known number of rotations are given to the screw head N, distance moved, on the pitch scale is noted and pitch is calculated., 2) The total number of divisions on the circular scale is noted., , 3) Least count is found., , KSPUPTF et er ee ; aT