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INCONSISTENCY IN CLASSICAL ELECTROSTATICS

September 21 2009 at 10:59 AM
 

 
The theory is based on the assumption that all of the forces are CONSERVATIVE:

W. Panofsky, M. Phillips, Classical Electricity and Magnetism, Addison-Wesley, Reading, Massachusetts (1962):
p.96: "By assembling these charges we have changed the energy of the system, and since all of the forces are conservative, we can identify this expression for the work of assembly with the energy of the system."
p.102: "The resultant energy expression is nevertheless general, since no nonconservative forces are involved."
p.103: "We must remember that the only physical fact underlying this discussion is Coulomb's law, the remainder of the discusion being mathematical, and therefore we cannot expect to obtain any physical concept regarding the mechanical interaction of charges which will add any physical facts beyond Coulomb's law."

Yet the fact that NONCONSERVATIVE forces are unavoidably involved is implicitly taken into account:

W. Panofsky, M. Phillips, Classical Electricity and Magnetism, Addison-Wesley, Reading, Massachusetts (1962):
p.100: "Thus we cannot equate the increment of the work done... to the increase in total energy, since heat transfers are also involved."
p.115: "Therefore the decrease in force... cannot be explained by electrical forces alone."
pp.115-116: "Thus the decrease in force that is experienced between two charges when they are immersed in a dielectric liquid can be understood only by considering the effect of the pressure of the liquid on the charges themselves. In accordance with the philosophy of the action-at-a-distance theory, no change in the purely electrical interaction between the charges takes place."

Pentcho Valev
pvalev@yahoo.com

 
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Anonymous

Re: INCONSISTENCY IN CLASSICAL ELECTROSTATICS

September 21 2009, 4:15 PM 

For sure PV must have worn out many books.
Yet he still unable to distinguish between microscopic laws and macroscopic laws.

 
 

Re: INCONSISTENCY IN CLASSICAL ELECTROSTATICS

September 23 2009, 5:16 AM 

The theory is based on the assumption that all of the forces are CONSERVATIVE:

W. Panofsky, M. Phillips, Classical Electricity and Magnetism, Addison-Wesley, Reading, Massachusetts (1962):
p.96: "By assembling these charges we have changed the energy of the system, and since all of the forces are conservative, we can identify this expression for the work of assembly with the energy of the system."
p.102: "The resultant energy expression is nevertheless general, since no nonconservative forces are involved."
p.103: "We must remember that the only physical fact underlying this discussion is Coulomb's law, the remainder of the discusion being mathematical, and therefore we cannot expect to obtain any physical concept regarding the mechanical interaction of charges which will add any physical facts beyond Coulomb's law."

Yet the fact that NONCONSERVATIVE forces are unavoidably involved is implicitly taken into account:

W. Panofsky, M. Phillips, Classical Electricity and Magnetism, Addison-Wesley, Reading, Massachusetts (1962):
p.100: "Thus we cannot equate the increment of the work done... to the increase in total energy, since heat transfers are also involved."
p.115: "Therefore the decrease in force... cannot be explained by electrical forces alone."
pp.115-116: "Thus the decrease in force that is experienced between two charges when they are immersed in a dielectric liquid can be understood only by considering the effect of the pressure of the liquid on the charges themselves. In accordance with the philosophy of the action-at-a-distance theory, no change in the purely electrical interaction between the charges takes place."

Another description of a non-conservative force in an electrostatic system:

http://www.amazon.com/Introduction-Electromagnetic-Theory-Modern-Perspective/dp/0763738271
Introduction to Electromagnetic Theory: A Modern Perspective
by Tai Chow
p. 267: "Calculations of the forces between charged conductors immersed in a liquid dielectric always show that the force is reduced by the factor K. There is a tendency to think of this as representing a reduction in the electrical forces between the charges on the conductors, as though Coulomb's law for the interaction of two charges should have the dielectric constant included in its denominator. This is incorrect, however. The strictly electric forces between charges on the conductors are not influenced by the presence of the dielectric medium. The medium is polarized, however, and the interaction of the electric field with the polarized medium results in an INCREASED FLUID PRESSURE ON THE CONDUCTORS that reduces the net forces acting on them."

Pentcho Valev
pvalev@yahoo.com

 
 

Re: INCONSISTENCY IN CLASSICAL ELECTROSTATICS

September 23 2009, 1:33 PM 

On Sep 23 John Polasek wrote in sci.physics:
> Pentcho Valev wrote:
> >The theory is based on the assumption that all of the forces are
> >CONSERVATIVE:
>
> >W. Panofsky, M. Phillips, Classical Electricity and Magnetism, Addison-
> >Wesley, Reading, Massachusetts (1962):
> >p.96: "By assembling these charges we have changed the energy of the
> >system, and since all of the forces are conservative, we can identify
> >this expression for the work of assembly with the energy of the
> >system."
> >p.102: "The resultant energy expression is nevertheless general, since
> >no nonconservative forces are involved."
> >p.103: "We must remember that the only physical fact underlying this
> >discussion is Coulomb's law, the remainder of the discusion being
> >mathematical, and therefore we cannot expect to obtain any physical
> >concept regarding the mechanical interaction of charges which will add
> >any physical facts beyond Coulomb's law."
>
> >Yet the fact that NONCONSERVATIVE forces are unavoidably involved is
> >implicitly taken into account:
>
> >W. Panofsky, M. Phillips, Classical Electricity and Magnetism, Addison-
> >Wesley, Reading, Massachusetts (1962):
> >p.100: "Thus we cannot equate the increment of the work done... to the
> >increase in total energy, since heat transfers are also involved."
> >p.115: "Therefore the decrease in force... cannot be explained by
> >electrical forces alone."
> >pp.115-116: "Thus the decrease in force that is experienced between
> >two charges when they are immersed in a dielectric liquid can be
> >understood only by considering the effect of the pressure of the
> >liquid on the charges themselves. In accordance with the philosophy of
> >the action-at-a-distance theory, no change in the purely electrical
> >interaction between the charges takes place."
>
> >Another description of a non-conservative force in an electrostatic
> >system:
>
> >http://www.amazon.com/Introduction-Electromagnetic-Theory-Modern-Perspective/dp/0763738271
> >Introduction to Electromagnetic Theory: A Modern Perspective
> >by Tai Chow
> >p. 267: "Calculations of the forces between charged conductors
> >immersed in a liquid dielectric always show that the force is reduced
> >by the factor K. There is a tendency to think of this as representing
> >a reduction in the electrical forces between the charges on the
> >conductors, as though Coulomb's law for the interaction of two charges
> >should have the dielectric constant included in its denominator. This
> >is incorrect, however. The strictly electric forces between charges on
> >the conductors are not influenced by the presence of the dielectric
> >medium. The medium is polarized, however, and the interaction of the
> >electric field with the polarized medium results in an INCREASED FLUID
> >PRESSURE ON THE CONDUCTORS that reduces the net forces acting on
> >them."
>
> Pentcho you evidently have this book and I hope you didn't pay $120.95
> for it on Amazon, where they also have a used one for $22.77. This one
> is 50 years after Panofsky and the same Neanderthal reasoning
> prevails. Tai Chow smoothly says "The medium is polarized, however,"
> without saying how this polarization is accomplished.
>
> I tried to explain it in my note above. One charge Q1 has so many
> coulombs per square meter, which when divided by K*eps turns into E
> volts per meter generating the force that works on Q2 coulombs.
>
> If the author wants to make his liquid force theory stick, he has to
> show how the electric field causes a pressure gradient in the liquid.
> Anything less than that means he is simply intoning the folklore of
> recitational physics.

I have explained how the field causes the mysterious pressure here:

http://wbabin.net/valev/valev2.pdf
BIASED THERMAL MOTION AND THE SECOND LAW OF THERMODYNAMICS

If you want to read the whole paper, note that the symbol for partial derivative (similar to " d ") may still be replaced by the symbol " ¶ " - at least the problem is not fixed for the moment.

Pentcho Valev
pvalev@yahoo.com

 
 
Anonymous

PV should go back to secondary school

September 24 2009, 10:20 AM 

The definition of the electrostatic potential involves the work done to displace a charge.
PV should remember that the definition also assumes that nothing changes in the surroundings during this displacement.
All other charges must be maintained in place.

Inconsitencies always pop up when the basics have not been fully understood.
Instead of browsing the net for physics that he can't understand, PV should read k-12 physics.

 
 
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