--%>
Assignment Help - homework help

What is Maxwells demon

Maxwell's demon (J.C. Maxwell): A contemplation experiment describing the concepts of entropy. We contain a container of gas that is partitioned into two equivalent sides; each side is in thermal equilibrium with the other. The walls and the separation of the container are ideal insulators.

Now suppose there is a very small demon who is waiting at the separation next to a small trap door. He can close and open the door with slight (negligible) work. Let's state he opens the door to permit a fast-moving molecule to travel from the left side to the right, or for a slow-moving molecule to travel from the right side to the left, and remains it closed for all other molecules. The total effect would be a flow of heat -- from left side to the right -- even although the container was in thermal equilibrium. This is obviously a violation of the second law of thermodynamics.

Thus where did we go wrong? It turns out that information has to do with entropy also. In order to sort out the molecules according to speeds, the demon would be containing to keep a memory of them -- and it turns out that rise in entropy of the maintenance of this simple memory would be more than make up for the reduction in entropy due to the flow of heat.

   Related Questions in Physics

  • Q : Define Machs principle Mach's principle

    Mach's principle (E. Mach; c. 1870): The inertia of any specific particle or particles of matter is attributable to the interaction among that piece of matter and the rest of the world. Therefore, a body in isolation would contain no inertia.

    		•
  • Q : Define Rayleigh criterion or resolving

    Rayleigh criterion: resolving power: The criterion for determining how delicately a set of optics might be able to differentiate. This  starts with the supposition that central ring of one image must fall on the first dark ring of the other; for

    		•
  • Q : Polar Materials The molecules of many

    The molecules of many dielectrics possess an electric dipole moment without having an external electric field. In such molecules centres of their positive and negative charges are displaced with respect to each other and therefore form a dipole. Such materials are kno

    		•
  • Q : Define Atwood's machine Atwood's

    Atwood's machine: The weight-and-pulley system devised to compute the acceleration due to gravity at Earth's surface by computing the total acceleration of a set of weights of identified mass about a frictionless pulley.

    		•
  • Q : Define Hall Effect Hall Effect:

    Hall Effect: Whenever charged particles flow via a tube that has both an electric field and a magnetic field (that is perpendicular to the electric field) present in it, only assured velocities of the charged particles are favored, and will make it un

    		•
  • Q : Explain Youngs experiment or

    Young's experiment: double-slit experiment (T. Young; 1801): A well-known experiment that exhibits the wave nature of light (and certainly of other particles). The light is passed from a small source into an opaque screen with the two thin slits. The

    		•
  • Q : What is Farad or SI unit of capacitance

    What is Farad or SI unit of capacitance? Farad: F (after M. Faraday, 1791-1867): The derived SI unit of the capacitance stated as the capacitance in a capacitor that, when charged to 1 C, contains

    		•
  • Q : How radiation emitted from the body

    Describe the procedure how radiation emitted from the body? Illustrate in brief.

    		•
  • Q : What do you mean by the term crest What

    What do you mean by the term crest? Briefly illustrate it.

    		•
  • Q : Define Watt or SI unit of power Watt: W

    Watt: W (after J. Watt, 1736-1819): The derived SI unit of power, stated as a power of 1 J acting over the period of 1 s; it therefore has the units of J/s.

    		•