Osm Physics by Ashish

When a real gas is allowed to flow adiabatically through a porous plug from a region of high pressure to a region of low pressure, its temperature may change. This phenomenon is known as the Joule–Thomson effect , and the process is called Joule–Thomson expansion or throttling . Porous Plug Experiment The apparatus used in the Joule–Thomson porous-plug experiment is shown schematically in Fig. Consider a gas flowing through a thermally insulated tube containing a porous plug P . Two weightless and frictionless pistons X and Y are fitted on the two sides of the plug. The entire system is thermally insulated; hence, no heat is exchanged with the surroundings. Initially, let the gas occupy chamber A , having ...

  A charged particle produces an electric field in the space surrounding it. When another charged particle is placed in this field, it experiences an electric force. Thus, the electric field provides a physical description of the influence of a charge on the space surrounding it. The electric field at a point is defined as the region of space around a charge or a system of charges in which another charged particle experiences an electric force. The concept of the electric field was developed by Michael Faraday . Electric field is a vector field , since it has both magnitude and direction. It is quantitatively described in terms of electric field intensity .   Intensity of Electric Field The electric field intensity at a point is defined as the force experienced by a unit positive test charge placed at that point: where is the force acting on the test charge . The test charge is assumed to be a very small positive point charge , so that its presence does not appreciably distu...