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Showing posts from January, 2019

Young's Modulus | Physics

Young's Modulus Our Objective Our aim is to determine the Young’s modulus of elasticity of the material of a given wire using Searle’s apparatus. The Theory Before we move ahead, do you know what a Searle’s apparatus is? Searle’s apparatus consists of two metal frames F1 and F2. Each frame has a torsion head at the upper side and a hook at the lower side. These frames are suspended from two wires AB and CD of same material, length and cross-section. The upper ends of the wires are screwed tightly in two torsion heads fixed in the same rigid support. A spirit level rests horizontally with  one end hinged in the frame F2. The other end of the spirit level rests on the tip of a spherometer screw, fitted in the frame F1. The spherometer screw can be rotated up and down along a vertical pitch scale marked in millimeters. The two frames are kept together by cross bars E1 and E2.  Do you know Searle’s apparatus works on the principle of Hooke’s law?  Hooke’s law can be e

Surface Tension | Physics

Surface Tension Objective To determine the surface tension of a liquid by capillary rise method. Theory How do you define surface tension? Surface tension is the property of a liquid, by virtue of which its free surface at rest behaves like an elastic skin or a stretched rubber membrane, with a tendency to contract so as to occupy minimum surface area. This property is caused by cohesion of molecules and is responsible for much of the behaviors of liquids. The property of surface tension is revealed, for example, by the ability of some objects to float on the surface of water, even though they are denser than water.  Surface tension is also seen in the ability of some insects, such as water striders, and even reptiles like basilisk, to run on the water’s surface.            The Theory Behind Surface Tension Surface tension has been well- explained by the molecular theory of matter. According to this theory, cohesive forces among liquid molecules are responsible

Viscosity of a Liquid \ Stokes Law | Physics

Viscocity of a Liquid \ Stokes Law Objective To determine the coefficient of viscosity of a given viscous liquid by measuring terminal velocity of a given spherical body. Theory How do you define viscosity?  Viscosity is the property of a fluid by virtue of which an internal resistance comes into play when the liquid is in motion, and opposes the relative motion between its different layers. Thus, it is the resistance of a fluid to flow. When liquid flows over flat surface, a backward viscous force acts tangentially to every layer. This force depends upon the area of the layer, velocity of the layer, and the distance of the layer from the surface.                                                                                                                                        Where η is the  coefficient of viscosity  of the liquid.   Stoke’s Law Stoke’s law was established by an English scientist Sir George G Stokes (1819-1903).  When a spherical body moves