what happens with an electric field when it did work on a charge?

[CARN0T]

Hello, guys,

Let me try an idea on you--

Suppose you have a bucket and you pour water into it.  And, at some other place on the bucket, you remove the water.  Can you think of a way to shape the bucket so that the amount of water you get out is greater than the water you put in?  Maybe adding some electric or magnetic fields, then can you get more water out than you put in?

Sounds simple, doesn't it? -- The bucket can't make more water, no matter what you do.

Why do some of you think energy is different?  It is just as immutable as the water.  Whatever energy you put into a device is exactly the energy you get out.  Simple.  This is the first law, and you must violate it to make a perpetual machine of the first kind.

Maybe we could save a lot of time on this forum by first asking where the extra energy is going to come from.   

If you can't answer the question, move on to a better idea.

Ernie Rogers

[Creativity]

I m clearly waiting here for an explanation where is the energy taken away from capacitor.It is instructive for all of us to learn to see possible flawns in designs.I set this play to excercise the brain.
So what happens to electric field after it did work on electric charge?
protons on positive plate won't reach the work function due to the shape of the plate.Charge is not lost there,so the strength of the field is not getting weaker ,even though electrons were accelerated in the field.

if u can't answer the question ur argument is getting weaker.

[CARN0T]

For some of us, your question doesn't require much exercise.  Since the field system you describe is static and conservative, no energy can be transferred to the charge without a change in potential between the starting point and the ending point.

Ernie Rogers

I m clearly waiting here for an explanation where is the energy taken away from capacitor.It is instructive for all of us to learn to see possible flawns in designs.I set this play to excercise the brain.
So what happens to electric field after it did work on electric charge?
protons on positive plate won't reach the work function due to the shape of the plate.Charge is not lost there,so the strength of the field is not getting weaker ,even though electrons were accelerated in the field.

if u can't answer the question ur argument is getting weaker.

[sparks]

@Creativity


    Expand your thought experiment to imagining the accelerating field also moving or accelerating.  Now those little charge carriers are really gonna get moving without effecting the polarizing scource.  Longitudinal waves suppose to be able to do this.

[CARN0T]

Creativity,

I thought more about your problem, and would like to say some more.

Notice that I allow for the charge to acquire energy if the field potential at the final point is different than at the starting point.  I wondered if your view made sense, that the energy transferred to the charge should appear as a reduction in field energy.  The potential energy of the particle (which is transferred to kinetic energy with its change in field potential)-- does that reside in the field or within the particle?  More broadly, when a rock rolls down a hill and gains kinetic energy, is there an equivalent decrease in energy within the gravitational field of the system?

I referred to my text book to refresh my understanding.  I found enlightenment in chapter 6 of "Classical Electricity and Magnetism" by Panofsky and Phillips.  I find that Maxwell had derived the energy in the field of a system, where the energy of an electrostatic field is the integral over the field of  e_o/2 E² dv, where e_o is the permitivity of free space.  (No dielectrics present.)

The book goes on to show that as the potential energy of a system of charges changes, the energy in the field changes by exactly the same amount.  One concludes that there surely is an analog for gravitation as well.

Ernie Rogers

For some of us, your question doesn't require much exercise.  Since the field system you describe is static and conservative, no energy can be transferred to the charge without a change in potential between the starting point and the ending point.

Ernie Rogers