A simple Q. but not a simple A,,
in [Physics]
|
Prev: ~~~~~~~~~~~~~~ FLIGHT RESERVATIONS ~~~~~~~~~~~~~~
Next: superlatives of Volcano-Electricity #47 Volcano-Electricity: Earth's Energy Future
From: Spencer Spindrift on 23 Jan 2010 11:27 On Dec 27 2009, 4:37 am, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: > Spencer Spindrift wrote: > > On 27 Dec, 00:37, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: > >> Spencer Spindrift wrote: > >> > Q.: How is it that a photon has momentum but no mass? > >> > Or in other words how does light carry energy? > >> > As far as I know momentum is a property of moving or spinning > >> > mass. > >> > A photon cannot have mass or it would be infinite at C.. > > >> > A.; ??? > > >> Fields carry energy and momentum. > > > Well that's a VERY simple answer. Please define "fields". There are fields of grass; magnetic and electric fields [ these have potential energy but I'm not aware that they carry momentum ]. I presume you mean EM fields. Wave/particle duality. Not a unified field.
From: kado on 23 Jan 2010 19:12 On Jan 23, 5:45 am, Spencer Spindrift <spencerspindr...(a)btinternet.com> wrote: > > I started this thread 251 posts ago with a simple question. > By now I think I've shown that there is no simple answer; hence the > 251 posts. The question was:- > How can a photon have momentum but not mass? > Of course a photon has no rest mass as it only exists at C, the speed > of light. Again- You are supposing that a photon has momentum, no rest mass... That is, this whole supposition is based on the assumption that photons exists, and not just an artifact...i.e., a 'red herring'. > I agree that a wave carries energy ..... Another assumption. When you can really prove, and not with round-about- mathematical equations that may not apply under the conditions, and/or that may not even be true- all the facts that apply to to your question, then maybe you can answer this for your self. Go back and really, and I mean really, study all my past posts to get some of the truths that apply to your conundrum AND get rid of all the dogmas within physics associated with your question that may instantly cloud your line of thinking. In other words; the mystery is really not too hard to resolve. > I am not one of them. I can use maths as a tool but it can never give > me any answers to satisfy my mind. Good for you. D.Y.K.
From: Inertial on 23 Jan 2010 19:19 <kado(a)nventure.com> wrote in message news:60dd1ab1-4bf4-47d4-b4f1-f64a51c31ff0(a)w12g2000vbj.googlegroups.com... > > > On Jan 23, 5:45 am, Spencer Spindrift > <spencerspindr...(a)btinternet.com> wrote: > >> >> I started this thread 251 posts ago with a simple question. >> By now I think I've shown that there is no simple answer; hence the >> 251 posts. The question was:- >> How can a photon have momentum but not mass? >> Of course a photon has no rest mass as it only exists at C, the speed >> of light. > > Again- You are supposing that a photon has momentum, > no rest mass... > That is, this whole supposition is based on the assumption > that photons exists, and not just an artifact...i.e., a 'red > herring'. There is something we detect, and we call it a photon. So that exists. It can have its momentum measured, and it is non-zero. It can have its (rest) mass measured and it is zero (to as accurately as we can measure) .. so no reason to think it is not as predicted. Note that though a photon has no rest mass, it does have a relativistic mass (ie the value you calculate from its energy or momentum) >> I agree that a wave carries energy ..... > > Another assumption. It is something we find experimentally. > When you can really prove, and not with round-about- > mathematical equations that may not apply under the > conditions, and/or that may not even be true- all the > facts that apply to to your question, then maybe you > can answer this for your self. It is something we find experimentally. > Go back and really, and I mean really, study all my past > posts to get some of the truths that apply to your > conundrum AND get rid of all the dogmas within physics > associated with your question that may instantly cloud > your line of thinking. > > In other words; the mystery is really not too hard to > resolve. > >> I am not one of them. I can use maths as a tool but it can never give >> me any answers to satisfy my mind. > > Good for you. > > > D.Y.K.
From: cjcountess on 23 Jan 2010 20:03 One more example of E=hf/c^2 http://www.plambeck.org/oldhtml/physics/physicspedestrian9.pdf page 119 problem 8-6c [PDF] C:\work\dellmigration\qxmail\websrc\html\physics\book ... - 6:41am File Format: PDF/Adobe Acrobat - View as HTML Light of frequency / is composed of photons of energy E = hf/c2. Show that the fractional energy loss for photons rising in a gravitational field ... www.plambeck.org/oldhtml/physics/physicspedestrian9.pdf Conrad J Countess
From: Inertial on 23 Jan 2010 20:18
"cjcountess" <cjcountess(a)yahoo.com> wrote in message news:2d959bbb-dadd-4afa-b1cc-661654ad3ba7(a)21g2000yqj.googlegroups.com... > One more example of E=hf/c^2 > http://www.plambeck.org/oldhtml/physics/physicspedestrian9.pdf > page 119 problem 8-6c It is wrong. Amazing you've found someone else as stupid as you. You do realize that this isn't a physics text .. it is notes from someone who is having troubles learning physics .. its clear why. E = hf NOT E = hf/c^2 Look at the units .. hf/c^2 has units of MASS ONLY. It is NOT an energy value !! AS the author says "here are my notes .. I can't imagine why anyone would want to read them" Really .. you're getting desperate now .. are you just googling thru every web pages trying to find someone else who made you mistake? Try again. |