What is your EM crankosity?
in [Relativity]
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From: Vince Morgan on 26 Sep 2009 05:17 "Benj" <bjacoby(a)iwaynet.net> wrote in message news:5e383309-0232-4441-9a7e-81e9c752d378(a)f10g2000vbf.googlegroups.com... > Are you a Maxwell loon? > How well do you understand Maxwell's equations? > Ten easy questions to measure your kookosity: > > 1. An electromagnetic plane wave in free vacuum consists of a > sinusoidal electric > field and a sinusoidal magnetic field at right angles to it. These > fields are delayed > 90 degrees from one another such that energy oscillates between them > in a > manner similar to an LRC circuit where the energy oscillates back and > forth > between capacitor storage and inductor storage. (true, false?) > > 2. A magnetic field changing strength in time causes an electric field > in space that is > capable of producing currents in conductors. The process is called > "induction" > and is described by Faraday's Law. (true, false?) > > 3. If a conducting circuit that encloses an area under a uniform > magnetic field that > totally covers the loop is changed in shape to enclose a different > amount of > magnetic flux, an emf will always be induced in the circuit due to the > changed > amount of flux. (true, false?) > > 4. When instruments measuring E and B (electric and magnetic fields) > that are > stationary with respect to those fields are placed on a moving > reference frame > moving with constant velocity with respect to the fields, by > relativity, the meters > always show the same values regardless of the magnitude of the > (constant) > velocity of the frame so long as the velocity of the moving frame is > much slower > than the speed of light. (true, false?) > > 5. For a point charge moving with a non-relativistic constant velocity > (not > accelerating) past an observer, the electric field from that charge > will be observed > to be the same spherical distribution found in electrostatics for a > non-moving > charge. (true, false) > > 6. According to Maxwell's Equations a time-changing electric field as > in a charging > or discharging capacitor creates a displacement current through that > capacitor and > that displacement current creates a magnetic field just as if the > capacitor were not > there and a wire carrying the current was producing the field. (true, > false?) > > 7. It can be shown that if a line charge segment is moving past you as > an observer at > some constant velocity, that not only does the apparent length of the > segment > change to the viewer, but by Lorentz contraction at relativistic > speeds the actual > length of the line charge segment changes as well. (true, false?) > > 8. It is well known through experiment and observations that > electromagnetic waves > as predicted by Maxwell's Equations form a spectrum depending on > frequency > that runs without other changes from low frequency radio waves, up > through > microwaves, on up to sub-millimeter waves, thence to Infrared light, > then visible > light, ultraviolet light and on up into X-rays and cosmic rays. > (true. false) > > 9. All electromagnetic clocks slow by the same amount as their frame > velocity > reaches significant relativistic speeds leading to the conclusion that > by relativity, a > "dilatation" of time takes place that affects all electromagnetic > events and even > including biological ones. (true , false?) > > 10. Electromagnetic waves as described by Maxwell's Equations, > propagate through > the vacuum of empty space by relationships observed from those > equations that a > changing electric field creates a magnetic field and a changing > magnetic field > creates an electric field. These waves are unique in that they do not > require a > medium to propagate in. (true, false?) > > ======================= > > Hey, Uncle Al, this test's for you! Show us your stuff now so we > won't have to call you "idiot"! Having followed this thread from start to end I just have to say *WOW* !! Never before have I been so pleased to know so little about anything. This post has exposed some astonishing ignorance. In fact I would like to suggest that this thread be preserved for posterity!! You've got balls Ben. Highest regards, Vince
From: Bill Miller on 26 Sep 2009 11:52 "Don Kelly" <dhky(a)shawcross.ca> wrote in message news:Jwfvm.75330$nQ6.73128(a)newsfe07.iad... > > You have made your point. Thanks again for your response. Do you need an > assistant to clean the toilets? > > > -- > Don Kelly > dhky(a)shawcross.ca > remove the x to reply Don.. Don't you dare! Now that Benj has been promoted to Janitor, I've applied for his old job. But I might need an assistant! Bill
From: Bill Miller on 26 Sep 2009 14:36 "John Kennaugh" <JKNG(a)notworking.freeserve.co.uk> wrote in message news:xhoKikMKGtuKFw3$@kennaugh2435hex.freeserve.co.uk... > blackhead wrote: >>On 23 Sep, 13:08, Benj <bjac...(a)iwaynet.net> wrote: >>> On Sep 23, 5:30 am, John Kennaugh <J...(a)notworking.freeserve.co.uk> >>> wrote: >>> <snip> > It is a simple enough question which you haven't answered. I would be > interested in your answer. > -- > John Kennaugh The question is simple enough. Restated, it is: "If the velocity of electron flow in a good conductor is so slow tha most people can walk faster than an electron can travel, how is it possible for electrons (ie measureable voltage) to appear at the far end of a cable essentially "instantaneously." The answer seems to elude more than a few folks. For example, in an otherwise excellent book on EM Field Theory, Guru and Hiziroglu say, "What happens in this case is that one electron that enters at the lower end of the wire *pushes* [emphasis mine] on the neighboring electron by means of its electric field and creates a compressional wave within the wire. The compressional wave travels with the speed of light and ejects electrons out of the the far end of the wire almost instantaneously. [!] In other words, the electrons "bump" into each other -- like pool balls lined up end to end! I don't think so! Let me make a "stab" at an alternate solution. First, I think it is necessary to recognize -- as Poynting surmised in his seminal paper -- that electrons are not the cause of energy flow in a conductor. Their actions are the result of energy flow associated with fields. So, here is what happens to explain the Catt Anomoly. An energy source is connected to a set of conductors. As soon as contact is made, field energy surrounds the conductors and begins flowing "on" them at nearly lightspeed. Inside the conductor, the electrons will begin "slogging" their way along at something like 24 mm/second. But something else is going on near the surface. The conductor is full of free electrons. (That's why it is a conductor.) Many of them are located just a few microns from the surface. If the field surrounding the conductor has a polarity such that it attracts electrons, those free electrons nearest the conductor's surface will move -- in a short time (With Respect To human reactions, but slower than lightspeed) -- onto the conductor's surface. A voltmeter will "instantly" show a negative voltage on its meter/display. Similarly, if the field repels electrons, they will move away from the surface and the voltmeter will show a positive voltage. But the energy to light the lightbulb or run the motor at the end of the conductors comes from the field, and not from the electron flow. All the best, Bill
From: Androcles on 26 Sep 2009 15:07 "Bill Miller" <billmillerkt4ye(a)worldnet.att.net> wrote in message news:7i7569F30fq6aU1(a)mid.individual.net... > > "John Kennaugh" <JKNG(a)notworking.freeserve.co.uk> wrote in message > news:xhoKikMKGtuKFw3$@kennaugh2435hex.freeserve.co.uk... >> blackhead wrote: >>>On 23 Sep, 13:08, Benj <bjac...(a)iwaynet.net> wrote: >>>> On Sep 23, 5:30 am, John Kennaugh <J...(a)notworking.freeserve.co.uk> >>>> wrote: >>>> > <snip> > >> It is a simple enough question which you haven't answered. I would be >> interested in your answer. >> -- >> John Kennaugh > > The question is simple enough. Restated, it is: "If the velocity of > electron flow in a good conductor is so slow tha most people can walk > faster than an electron can travel, how is it possible for electrons (ie > measureable voltage) to appear at the far end of a cable essentially > "instantaneously." > > The answer seems to elude more than a few folks. For example, in an > otherwise excellent book on EM Field Theory, Guru and Hiziroglu say, "What > happens in this case is that one electron that enters at the lower end of > the wire *pushes* [emphasis mine] on the neighboring electron by means of > its electric field and creates a compressional wave within the wire. The > compressional wave travels with the speed of light and ejects electrons > out of the the far end of the wire almost instantaneously. [!] > > In other words, the electrons "bump" into each other -- like pool balls > lined up end to end! I don't think so! > > Let me make a "stab" at an alternate solution. > > First, I think it is necessary to recognize -- as Poynting surmised in his > seminal paper -- that electrons are not the cause of energy flow in a > conductor. Their actions are the result of energy flow associated with > fields. > > So, here is what happens to explain the Catt Anomoly. > > An energy source is connected to a set of conductors. As soon as contact > is made, field energy surrounds the conductors and begins flowing "on" > them at nearly lightspeed. > > Inside the conductor, the electrons will begin "slogging" their way along > at something like 24 mm/second. > > But something else is going on near the surface. > > The conductor is full of free electrons. (That's why it is a conductor.) > Many of them are located just a few microns from the surface. > > If the field surrounding the conductor has a polarity such that it > attracts electrons, those free electrons nearest the conductor's surface > will move -- in a short time (With Respect To human reactions, but slower > than lightspeed) -- onto the conductor's surface. A voltmeter will > "instantly" show a negative voltage on its meter/display. > > Similarly, if the field repels electrons, they will move away from the > surface and the voltmeter will show a positive voltage. > > But the energy to light the lightbulb or run the motor at the end of the > conductors comes from the field, and not from the electron flow. > > All the best, > > Bill When assisting Benj to lay turf, always remember "green side up".
From: Bill Miller on 26 Sep 2009 16:05
"Androcles" <Headmaster(a)Hogwarts.physics_o> wrote in message news:1Etvm.201494$tD4.128637(a)newsfe07.ams2... > > > When assisting Benj to lay turf, always remember "green side up". > When dealing with Androcles, remember that he prefers Astroturf. It has no roots, can be placed either way up, and he has no idea when he has used it incorrectly. All the best, Bill |