Ideal Gas Law

An equation which sums up the ideal gas laws in one simple equation P V = n R T,

Joule-Thomson Effect; Joule-Kelvin Effect

The change in temperature that occurs when a gas expands into a region of lower pressure.

Joule's Laws

Joule's first law

The heat Q produced when a current I flows through a resistance R for a specified time t is given by Q = I ² R t.

Kirchhoff's Rules

» loop rule

The sum of the potential differences encountered in a round trip around any closed loop in a circuit is zero.

» point rule

The sum of the currents toward a branch point is equal to the sum of the currents away from the same branch point.

Kohlrausch's Law

If a salt is dissolved in water, the conductivity of the solution is the sum of two values -- one depending on the positive ions and the other on the negative ions

Lambert's Laws

Lambert's first law

The illuminance on a surface illuminated by light falling on it perpendicularly from a point source is proportional to the inverse square of the distance between the surface and the source.

Lambert's second law

If the rays meet the surface at an angle, then the illuminance is proportional to the cosine of the angle with the normal.

Lambert's third law

The luminous intensity of light decreases exponentially with distance as it travels through an absorbing medium.

Laplace Equation

For steady-state heat conduction in one dimension, the temperature distribution is the solution to Laplace's equation, which states that the second derivative of temperature with respect to displacement is zero.

Lenz's Law (1835)

An induced electric current always flows in such a direction that it opposes the change producing it.

Mach Number

The ratio of the speed of an object in a given medium to the speed of sound in that medium.

Mach's Principle (1870)

The inertia of any particular particle or particles of matter is attributable to the interaction between that piece of matter and the rest of the Universe. Thus, a body in isolation would have no inertia.

Maxwell's Equations (1864)

Gauss' law

The electric flux through a closed surface is proportional to the algebraic sum of electric charges contained within that closed surface; in differential form div E = rho, where rho is the charge density.

Gauss' law for magnetic fields

The magnetic flux through a closed surface is zero; no magnetic charges exist. In differential form div B = 0.

Faraday's law

The line integral of the electric field around a closed curve is proportional to the instantaneous time rate of change of the magnetic flux through a surface bounded by that closed curve; in differential form curl E = -d B /d t,..

Ampere's law, modified form

The line integral of the magnetic field around a closed curve is proportional to the sum of two terms: first, the algebraic sum of electric currents flowing through that closed curve; and second, the instantaneous time rate of change of the electric flux through a surface bounded by that closed curve; in differential form curl H = J + d D /d t,.

In addition to describing electromagnetism, his equations also predict that waves can propagate through the electromagnetic field, and would always propagate at the the speed of light in vacuum.

Murphy's Law (1942)

If anything can go wrong, it will.

Дата добавления: 2015-11-16