HO-ED-INT-02 Cornus Interference Apparatus

Cornus Interference Apparatus This device is similar to Newton's Rings apparatus, except that an arrangement for loading the test piece is provided for carrying out Cornus interference studies. The objective of this experiment is to determine Poisson's ratio and Young's Modulus for different materials (glass, Perspex etc) using interference method. Weights are positioned at both ends of the bar, causing it to bend longitudinally downward. A glass plate is placed on the bar to produce an interference pattern. By examining the interference pattern, extent of longitudinal and lateral bending can be determined. Thus, Poisson ratio and Young's modulus of the bar can be deduced. When a plano-convex lens rests on a uniformly bent glass bar, an air film is formed between the two surfaces. Without adding any mass in the weight hanger we get circular rings. But as we uniformly add mass on the weight hangers, the beam bends and we get elliptical fringes. Experiment: To study the elastic constants of glass by Cornus interference methods,    i.    Hyperbolic fringes When a rectangular glass plate rests on a uniformly bent glass beam, an air film is formed between the two glass surfaces. On illuminating the air film with monochromatic light, two conjugate systems of hyperbolic fringes (longitudinal and transverse) around the point of contact of the glass plates are obtained. By measuring the longitudinal and transverse curvature, Young’s modulus (Y) and Poisson’s ratio (σ) can be determined.    ii.    Elliptical fringes When a plano-convex lens rests on a uniformly bent glass bar, an air film is formed between the two surfaces. On illuminating the air film with monochromatic light, a system of elliptical fringes (longitudinal and transverse) around the point of contact of the glass bar is obtained. By measuring the longitudinal and transverse curvature, Young’s modulus (Y) and Poisson’s ratio (σ) can be determined. Specifications:    Travelling Microscope     Magnification     10 x     Micrometer travel     25 mm     Least count     0.01 mm Features:   In this apparatus, sodium vapor lamp and spectral LED's are used as light sources     Traveling microscope with precision micrometer is used for accurate measurements     High quality optics are used in order to get the clear fringe pattern     All materials used in this setup are of laboratory grade and are corrosion resistant Drawings:  Related Topics:   Young's Modulus     Poisson's ratio     Rigidity Modulus     Bulk Modulus   Scope of Delivery: Travelling Microscope with Rigid Base Knife Edges with Rigid Base LED Mount with Rigid Base Weight Hanger Clamp Weight Hangers with Weight Plano Convex Lens Plano Convex Lens Optical Flat Beamsplitter Plate Sodium vapor lamp with Power Supply LED's with Power supply Test Samples Accessories Dust Protective cover Instruction Manual