Реферат: Физические законы, переменные, принципы
Compton effect (A.H. Compton; 1923)
An effect that demonstrates that photons (the quantum ofelectromagnetic radiation) have momentum. A photon fired at astationary particle, such as an electron, will impart momentum tothe electron and, since its energy has been decreased, willexperience a corresponding decrease in frequency.
Coriolis pseudoforce (G. de Coriolis; 1835)
A pseudoforce -- a fictitious force, like the centrifugal "force"-- which arises because the rotation of the Earth varies atdifferent latitutdes (maximum at the equator, zero at the poles).
correspondence principle.
The principle that when a new, more specialized theory is putforth, it must reduce to the more general (and usually simpler)theory under normal circumstances. There are correspondenceprinciples for general relativity to special relativity andspecial relativity to Newtonian mechanics, but the most widelyknown correspondence principle (and generally what is meant whenone says "correspondence principle") is that of quantum mechanicsto classical mechanics.
Cosmic background radiation; primal glow
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Cosmological redshift
An effect where light emitted from a distant source appearsredshifted because of the expansion of space itself. Compare withthe Doppler effect.
Coulomb's law
The primary law for electrostatics, analogous to Newton's law ofuniversal gravitation. It states that the force between two pointcharges is proportional to the algebraic product of theirrespective charges as well as proportional to the inverse squareof the distance between them.
CPT theorem
Curie-Weiss law (P. Curie, P.-E. Weiss)
A more general form of Curie's law, which states that thesusceptibility of a paramagnetic substance is inverselyproportional to the thermodynamic temperature of the substanceless the Weiss constant, a characteristic of that substance.
Curie's law (P. Curie)
The susceptibility of a paramagnetic substance is inverselyproportional to the thermodynamic temperature of the substance.The constant of proportionality is called the Curie constant.
Dalton's law of partial pressures (J. Dalton)
The total pressure of a mixture of ideal gases is equal to the sumof the partial pressures of its components; that is, the sum ofthe pressures that each component would exert if it were presentalone and occuped the same volume as the mixture.
Davisson-Germer experiment (C.J. Davisson, L.H. Germer; 1927)
An experiment that conclusively confirmed the wave nature ofelectrons; diffraction patterns were observed by an electron beampenetrating into a nickel target.
De Broglie wavelength (L. de Broglie; 1924)
The prediction that particles also have wave characteristics,where the effective wavelength of a particle would be inverselyproportional to its momentum, where the constant ofproportionality is the Planck constant.
Doppler effect (C.J. Doppler)
Waves emitted by a moving observer will be blueshifted(compressed) if approaching, redshifted (elongated) if receding.It occurs both in sound as well as electromagnetic phenomena,although it takes on different forms in each.
Dulong-Petit law (P. Dulong, A.T. Petit; 1819)
The molar heat capacity is approximately equal to the three timesthe gas constant.
Einstein-Podolsky-Rosen effect
Consider the following quantum mechanical thought-experiment:Take a particle which is at rest and has spin zero. Itspontaneously decays into two fermions (spin 0.5 particles), whichstream away in opposite directions at high speed. Due to the lawof conservation of spin, we know that one is a spin +0.5 and theother is spin -0.5. Which one is which? According to quantummechanics, neither takes on a definite state until it is observed(the wavefunction is collapsed).
The EPR effect demonstrates that if one of the particles isdetected, and its spin is then measured, then the other particle-- no matter where it is in the Universe -- instantaneously isforced to choose as well and take on the role of the otherparticle. This illustrates that certain kinds of quantuminformation travel instantaneously; not everything is limited bythe speed of light.
However, it can be easily demonstrated that this effect doesnot make faster-than-light communication possible.
Equivalence principle
The basic postulate of A. Einstein's general theory of relativity,which posits that an acceleration is fundamentallyindistinguishable from a gravitational field. In other words, ifyou are in an elevator which is utterly sealed and protected fromthe outside, so that you cannot "peek outside," then if you feel aforce (weight), it is fundamentally impossible for you to saywhether the elevator is present in a gravitational field, orwhether the elevator has rockets attached to it and isaccelerating "upward."
The equivalence principle predicts interesting generalrelativistic effects because not only are the twoindistinguishable to human observers, but also to the Universe aswell, in a way -- any effect that takes place when an observer isaccelerating should also take place in a gravitational field, andvice versa.
Ergosphere
The region around a rotating black hole, between the event horizonand the static limit, where rotational energy can be extractedfrom the black hole.
Event horizon
The radius of surrounding a black hole at which a particle wouldneed an escape velocity of lightspeed to escape; that is, thepoint of no return for a black hole.
Faraday constant; F (M. Faraday)
The electric charge carried by one mole of electrons (or singly-ionized ions). It is equal to the product of the Avogadroconstant and the (absolute value of the) charge on an electron; itis
9.648670.104 C/mol.
Faraday's law (M. Faraday)
The line integral of the electric flux around a closed curve isproportional to the instantaneous time rate of change of themagnetic flux through a surface bounded by that closed curve.
Faraday's laws of electrolysis (M. Faraday)
1. The amount of chemical change during electrolysis is proportional to the charge passed.
2. The charge required to deposit or liberate a mass is proportional to the charge of the ion, the mass, and inversely proprtional to the relative ionic mass. The constant of proportionality is the Faraday constant.
Faraday's laws of electromagnetic induction (M. Faraday)
1. An electromotive force is induced in a conductor when the magnetic field surrounding it changes.
2. The magnitude of the electromotive force is proportional to the rate of change of the field.
3. The sense of the induced electromotive force depends on the direction of the rate of the change of the field.
Fermat's principle; principle of least time (P. de Fermat)
The principle, put forth by P. de Fermat, states that the pathtaken by a ray of light between any two points in a system isalways the path that takes the least time.
Fermi paradox
E. Fermi's conjecture, simplified with the phrase, "Where arethey?" questioning that if the Galaxy is filled with intelligentand technological civilizations, why haven't they come to us yet?There are several possible answers to this question, but since weonly have the vaguest idea what the right conditions for life andintelligence in our Galaxy, it and Fermi's paradox are no morethan speculation.
Gauss' law (K.F. Gauss)
The electric flux through a closed surface is proportional to thealgebraic sum of electric charges contained within that closedsurface.
Gauss' law for magnetic fields (K.F. Gauss)
The magnetic flux through a closed surface is zero; no magneticcharges exist.
Grandfather paradox
A paradox proposed to discount time travel and show why itviolates causality. Say that your grandfather builds a timemachine. In the present, you use his time machine to go back intime a few decades to a point before he married his wife (yourgrandmother). You meet him to talk about things, and an argumentensues (presumably he doesn't believe that you're hisgrandson/granddaughter), and you accidentally kill him.
If he died before he met your grandmother and never hadchildren, then your parents could certainly never have met (one ofthem didn't exist!) and could never have given birth to you. Inaddition, if he didn't live to build his time machine, what areyou doing here in the past alive and with a time machine, if youwere never born and it was never built?
