Electromagnetic Waves: Why Accelerating Charges?

[mufa]

I appreciate your condescension.Unfortunately,I am not a student and I have not free time to study in depth.That's why I threw the ball to you.

 

[sophiecentaur]

I appreciate your condescension.Unfortunately,I am not a student and I have not free time to study in depth.That's why I threw the ball to you.

Sorry about my 'tone'. You seemed fairly well informed and a bit 'combative' (?) and I was a bit too ready to pick up my cudgel.
Any way, why should Photons have no mass?
I think that there is experimental evidence in which it has been attempted to infer their rest mass. This is based on splitting their Energy into two components
E = p²c² + m_restc²
where p is the momentum (which can be measured)
Looking for a discrepancy between the measured E and the energy due to the momentum gives an upper limit of the m_restc² component of 10^-17eV, (very small but, of course, an experiment can't yield a totally zero value).
So that's a fairly good justification for assuming it's zero and it would seem to go along with relativity as a model.
This is a good link about it.

 

[mufa]

They are referred to the "moving" mass to be zero:m=p/c.This is my point of disagreement.I think that mass cannot be completely vanished.It can be estimated by de Broglie equation:m=h/λc=hf/c^2. I believe that mass decreases with speed following a formula like this:m=m(rest)α^υ, 0<<α<1,υ=velocity, so it cannot be disappeared at all.Thank you for the link.I'm a mensa member just curious about physics.

 

[sophiecentaur]

Not sure what mensa has to do with this but I guess it implies that you are competent to read around the subject in depth. If you do that then you may find that there is more to it than just the de Broglie thing. In any case, de Broglie's idea was introduced in order to deal with the behaviour of particles with Mass.

 

[shivaniits]

so basically i was considering the speed of the charges inside wire defined by the drift velocity and speed of electric waves that's equal to speed of light..so my point is if electric waves don't carry any charge (as mostly light that we encounter from sun's radiation is em and since they don't carry any charge we don't get shock)so what do they actually carry..i was trying to figure out its resemblance to mechanical waves ..as mechanical wave don't itself carry any matter with it they only transfer energy..then so do the electric waves they can't carry charge but they must transfer energy in the form of you know electric waves..or could i say now that these electric waves are source of electric field..then thing that's confusing me is that if electric field propagates at speed of light(speed of electric waves)..then do the voltage that we define as eL or voltage or potential at a point is=electric field intensity * L(distance) then should the voltage drop or potential also varies accordingly or i could say that the potential also following the electric field intensity at the speed of light..but this is contradictory to our general observation in which we define particular time period and phasors which define variation of voltage that..so not at the speed of light..

 

[Drakkith]

Light itself is an electromagnetic wave that carries energy with it, just like all waves do. As for the velocity of electric fields inside conductors, I believe that is less than c, but I don't know any details on it.

 

[WJE]

Good day, i have a different question...

I need a core for an Electro Magnet which will be able to be as strong as possible when it has a current applied, but will not be attracted to a permanent magnet when the current is turned off. The core must lose its magnetic properties as soon as the current is removed so that it can be switched on and off.
(i.e. Steel can become a strong electro magnet, but will be attracted to a permanent magnet with or without a current, therefore I cannot use it.)
To make the experiment work as effectively as possible the core should be able to be converted to an electromagnet with minimal current, I thought about using Ferrite (Manganese Zinc) Round Bar? What will be the best gauge to use to get a strong magnet, but keep the current "voltage" as low as possible, even if is not as strong, i only require it to react with a neodymium magnet from a distance of at least 50mm - 100 mm. Do you have any suggestions on this topic?

 

[Drakkith]

WJE your best bet is to make a new thread with your question.