Physics Technical Reference

lecturesGR

T he effects of magnetism follow from the fact that moving charges see current-carrying wires as charged, due to relativistic length contraction which upsets the wire's apparent charge balance. Hence from special relativity and the fact that opposite charges attract, one can show that like currents in neutral wires attract . This is illustrated with a couple of x-ct plots below. Relativistic Electrostatics => Magnetism

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Physics is an experimental science, and as such the experimental basis for any physical theory is extremely important. The relationship between theory and experiments in modern science is a multi-edged sword: It is required that the theory not be refuted by any undisputed experiment within the theory's domain of applicability . It is expected that the theory be confirmed by a number of experiments that: cover a significant fraction of the theory's domain of applicability . examine a significant fraction of the theory's predictions. At present, Special Relativity (SR) meets all of these requirements and expectations. There are literally hundreds of experiments that have tested SR, with an enormous range and diversity, and the agreement between theory and experiment is excellent. Experimental Basis of Special Relativity

George Jones has probably already answered the question but here's a few equations that you might find of interest- In all cases a=J/mc and M=Gm/c 2 Radius of a black hole

The Rindler Horizon by Greg Egan This web page was inspired by a discussion on the Usenet group sci.physics.research entitled “The Black Fishing Hole”, in which Edward Green asked for an account of precisely what would happen if someone lowered an object through a black hole's horizon on a fishing line. I gave a reply describing a slightly different, but related, scenario: that of a constantly accelerating observer in flat spacetime trailing an object behind them. Darryl McCullough made the connection explicit, pointing out that a first-order approximation of the Schwarzschild metric near a black hole's horizon gives a coordinate system for flat spacetime describing just such a class of observers. The purpose of this web page, then, is to analyse in detail (using only special relativity) some interesting thought experiments that can be carried out by a constantly accelerating observer, who sees a “Rindler horizon” in spacetime that is very similar to the event horizon of a black hole.

Click here to go to the UPSCALE home page. Click here to go to the JPU200Y home page. Click here to go to the Physics Virtual Bookshelf. Gravitational Time Dilation

[Physics FAQ] - [Copyright] Updated by Terence Tao 1997. Original by Philip Gibbs 1996. Suppose an object A is moving with a velocity v relative to an object B , and B is moving with a velocity u (in the same direction) relative to an object C . Relativistic Velocities

Mass increase at relativistic speeds Until now, I always that that a relativistic mass increase was literally just the increase in the mass of an object. Today I googled it, and a couple sources say that it is just an increase in energy, not mass. Can anyone confirm this? At first I thought if the mass increased, then it would take more energy to accelerate that mass, and eventually it would take infinite energy. But if its really energy that increases, then this logic doesn't make sense. Unless it still takes more energy to accelerate a particle with a higher energy?

Bell's Theorem Click here to go to the Physics Virtual Bookshelf In 1975 Stapp called Bell's Theorem "the most profound discovery of science." Note that he says science , not physics . I agree with him.

A question about nonlocality It sounds to me as if he was just using "metaphysical" to talk about the idea that the outcome of each measurement is determined by preexisting hidden variables--if the variables are assumed to be "hidden" then this isn't really an ordinary physical hypothesis, so one can call it metaphysical. What do you mean by "mathematical properties that are not easy to imagine"? The issue is simply that the mathematical properties are not compatible with local hidden variables theories--basically, any theory where the world can be described entirely in terms of localized facts (like the momentum of a particular particle at a given point in spacetime), and where any given fact (including the result of a measurement) can only be influenced by other facts which lie in its past light cone.

Bell Theorem This make no sense.

First published Mon Aug 13, 2001; substantive revision Thu Aug 26, 2010 Quantum entanglement is a physical resource, like energy, associated with the peculiar nonclassical correlations that are possible between separated quantum systems. Entanglement can be measured, transformed, and purified. A pair of quantum systems in an entangled state can be used as a quantum information channel to perform computational and cryptographic tasks that are impossible for classical systems. The general study of the information-processing capabilities of quantum systems is the subject of quantum information theory. 1. Quantum Entanglement and Information

Britney Spears' Guide to Semiconductor Physics - Lasers and Optoelectronics

AC Circuits Alternating current Direct current (DC) circuits involve current flowing in one direction. In alternating current (AC) circuits, instead of a constant voltage supplied by a battery, the voltage oscillates in a sine wave pattern, varying with time as: In a household circuit, the frequency is 60 Hz. The angular frequency is related to the frequency, f, by: