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Jan16-12 Greg Bernhardt
Contributed by ZapperZ and arildno. This question has popped up many times. So here is an attempt to address it. ...
May25-09 10:31 AM
ZapperZ
0 25,700
Do Photons Move Slower in a Solid Medium? Contributed by ZapperZ. Edited and corrected by Gokul43201 and inha ...
Feb2-06 07:47 PM
ZapperZ
0 11,526
WHY DONíT ELECTRONS CRASH INTO THE NUCLEUS IN ATOMS? Contributed by Marlon and edited by ZapperZ If one...
Dec20-05 01:14 PM
ZapperZ
0 9,985
This forum contains simple responses to the most frequently-asked questions in the Physics sub-forums. It is a...
Dec20-05 01:13 PM
ZapperZ
0 8,736
IS LIGHT A WAVE OR A PARTICLE? Contributed by Marlon and ZapperZ. In our ordinary world, “wave” and “particle”...
Dec28-05 01:43 PM
ZapperZ
0 7,900
Contributed by vanesch. The short answer is: no, there's no violation. The longer answer can be this: Given the...
May11-06 10:35 AM
ZapperZ
0 7,217
heat Sticky Thread Pinned: What is Heat?
Written by Hootenanny. Edited by berkeman and Kurdt. Feel free to contact me with any questions, comments or...
Feb3-08 12:04 PM
Hootenanny
0 7,175
Definition/Summary Work is a measure of change of energy. The net work done equals the change in Kinetic Energy...
T 11:39 AM
Greg Bernhardt
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Definition/Summary Virtual particles are a mathematical device used in perturbation expansions of the S-operator...
T 11:35 AM
Greg Bernhardt
0 36
Definition/Summary Voltage is electric potential difference, which is potential energy difference per charge: V\ =\...
T 11:36 AM
Greg Bernhardt
0 36
Definition/Summary Vectors (such as velocity or force or momentum) obey the Vector Law of Addition. That means...
T 11:35 AM
Greg Bernhardt
0 35
Definition/Summary The trick is to change a difficult integral into an easier integral by treating a constant as a...
T 09:29 AM
Greg Bernhardt
0 32
Definition/Summary Inertia is the phenomenon that a force is required to cause change of velocity. The amount of...
T 10:31 AM
Greg Bernhardt
0 31
Definition/Summary Take the case of a string with it's one end tied to a wall. The other end is held by you. It...
T 11:38 AM
Greg Bernhardt
0 31
Definition/Summary One of the most asked questions is concerning how to derive the Heisenberg Uncertainty Relation....
T 11:34 AM
Greg Bernhardt
0 29
Definition/Summary In thermodynamics, internal energy, U, is the energy associated with the microscopic energies of...
T 10:36 AM
Greg Bernhardt
0 29
Definition/Summary Stress is force per area, and is a tensor. It is measured in pascals (Pa), with dimensions of...
T 11:29 AM
Greg Bernhardt
0 29
Definition/Summary A non-inertial observer measures the same "real" (physical) forces as an inertial observer does,...
T 09:12 AM
Greg Bernhardt
0 28
Definition/Summary Hamilton's equations of motion is a very general equation of a system evolving deterministically...
T 10:22 AM
Greg Bernhardt
0 28
Definition/Summary Force = impulse per time: \mathbf{F}\ =\ d\mathbf{I}/dt. For constant force, impulse = force...
T 10:29 AM
Greg Bernhardt
0 28
Definition/Summary A Slater determinant is a representation of a many-particle wave function for a system of...
T 11:26 AM
Greg Bernhardt
0 28
Definition/Summary A collision is said to be inelastic if the total kinetic energy of all the bodies involved in...
T 10:30 AM
Greg Bernhardt
0 27
Definition/Summary Snell's Law relates the angles of incidence and refraction, for a light ray that passes between...
T 11:27 AM
Greg Bernhardt
0 27
Definition/Summary This is a derivation of the Uncertainty Principle based on the properties of non-commuting...
T 11:33 AM
Greg Bernhardt
0 27
Definition/Summary The Hamiltonian, like the Lagrangian, is a function that summarizes equations of motion. It has...
T 10:24 AM
Greg Bernhardt
0 26
Definition/Summary The impedance of a load (a combination of components) in an AC current is a complex number Z\ =\...
T 10:29 AM
Greg Bernhardt
0 26
Definition/Summary Intensity of radiation = power per area perpendicular to the radiation. It is a vector, parallel...
T 10:32 AM
Greg Bernhardt
0 26
Definition/Summary Susceptibility is a property of material. In a vacuum it is zero. Susceptibility is an...
T 11:29 AM
Greg Bernhardt
0 26
Definition/Summary Coulomb's law is an inverse-square law stating that the force vector between two stationary...
T 09:28 AM
Greg Bernhardt
0 25
Definition/Summary A hydrogen-like or hydrogenic atom is a two-body system where the particles are bound by an...
T 10:28 AM
Greg Bernhardt
0 25
Definition/Summary Friction is a force which opposes relative motion when two solid bodies are in contact. A...
T 10:16 AM
Greg Bernhardt
0 25
Definition/Summary A Gaussian beam is an electromagnetic wave, usually a laser beam, with a Gaussian...
T 10:18 AM
Greg Bernhardt
0 25
Definition/Summary Heat is the non-mechanical exchange of internal energy, U, between a system and its surroundings...
T 10:25 AM
Greg Bernhardt
0 25
Definition/Summary The Hermitian transpose or Hermitian conjugate (or conjugate transpose) M^{\dagger} of a matrix...
T 10:26 AM
Greg Bernhardt
0 25
Definition/Summary The double-slit (or 'two-slit') experiment clearly demonstrates that individual particles...
T 11:38 AM
Greg Bernhardt
0 25
Definition/Summary The Hamilton-Jacobi equation is an additional reformulation of classical mechanics, one that...
T 10:23 AM
Greg Bernhardt
0 24
Definition/Summary A spring is a mechanical device that produces a restoring force when stretched or compressed....
T 11:28 AM
Greg Bernhardt
0 24
Definition/Summary Torque is the moment of a force about a point. Torque is a vector (strictly, a pseudovector,...
T 11:32 AM
Greg Bernhardt
0 24
Definition/Summary A wave function is a mathematical function that describes a physical system in quantum...
T 11:37 AM
Greg Bernhardt
0 24
Definition/Summary Centripetal acceleration of something moving in a circle is the component of its acceleration...
T 09:17 AM
Greg Bernhardt
0 23
Definition/Summary Gauge invariance is a form of symmetry. An experiment here today will work the same way over...
T 10:17 AM
Greg Bernhardt
0 23
Definition/Summary A particular choice of "gauge fields" in which the vector potential has no divergence. ...
T 09:27 AM
Greg Bernhardt
0 23
Definition/Summary This term most commonly refers to the number of quantum states having energy within a given...
T 09:28 AM
Greg Bernhardt
0 23
Definition/Summary Coriolis force is a non-physical force, appearing, like centrifugal force, only in rotating...
T 09:26 AM
Greg Bernhardt
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Definition/Summary A capacitor (or condenser) is something across which charge cannot move, but across which an...
T 09:10 AM
Greg Bernhardt
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Definition/Summary A force is conservative (the following definitions are all equivalent): if it complies with...
T 09:23 AM
Greg Bernhardt
0 22
Definition/Summary Time-order means in order of time. A sequence or product is in time-order if "earlier" items are...
T 11:31 AM
Greg Bernhardt
0 22

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