--%>

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 : Explain Thermodynamic laws Explain

    Explain Thermodynamic laws and also First law, Second law, third law and zeroth law of thermodynamics? Thermodynamic laws:

    Q : Define Centrifugal pseudo force

    Centrifugal pseudo force: A pseudo force which takes place whenever one is moving in uniform circular motion. One feels a "force" directed outward from the center of the motion.

  • Q : Define Van der Waals force Van der

    Van der Waals force (J.D. van der Waals): The forces responsible for non-ideal behavior of gases, and for lattice energy of molecular crystals. There are three main causes: dipole-dipole interaction; dipole-induced dipole moments; and dispersion a for

  • Q : Define Tipler machine Tipler machine:

    Tipler machine: The solution to Einstein's equations of general relativity which permits time travel. A tremendously dense (that is, on the order of the density of neutron star matter), infinitely-long cylinder that rotates very quickly can form close

  • Q : What is Boltzmann constant Boltzmann

    Boltzmann constant: k (L. Boltzmann) - The constant that explains the relationship between kinetic energy and temperature for molecules in an ideal gas. This is equivalent to the 1.380 622 x 10-23 J/K.

  • Q : What is Negative feedback principle

    Negative feedback principle: It is the idea that in a system where there are self-propagating situations, those new situations tend to act against formerly existing situations. Such a principle is in actuality a restatement of the conservation law.

  • Q : Branches of physics Briefly list out

    Briefly list out the name of all the branches of physics?

  • Q : Explain Superposition principle and

    Explain Superposition principle and their illustrations? Superposition principle: The common idea that, whenever a number of influences are performing on a syst

  • Q : Define Sievert or SI unit of dose

    Sievert: Sv: The derived SI unit of dose equivalent, stated as the absorbed dose of the ionizing radiation multiplied by internationally-agreed-upon dimensionless weights, as various kinds of ionizing radiation cause various kinds of damage in the liv

  • Q : Explain Ideal gas equation Ideal gas

    Ideal gas equation: The equation that sums up the ideal gas laws in one simple equation, P V = n R T, Here V is the volume, P is the pressure, n is the