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Re: Why does electrostatic attraction in water decrease?



Pentcho Valev wrote:

Please see fig. 6-7 on p. 112 in Panofsky.

I don't have easy access to that.

A capacitor
with vertical plates is only partially immersed into a pull of liquid,
and the liquid inside the capacitor has risen high above the surface of
the pull. Now punch a hole in one of the capacitor plates, above the
surface of the pull but below the surface of the liquid inside the
capacitor. Will the liquid leak out through the hole? I would be very
surprised if it does not.

I would be very surprised if it did.

-- We could run a water-wheel using the water that leaks out of
the hole, and have a nice perpetual-motion machine.

-- To say the same thing in other words, there will be a force
on the liquid due to the field-gradient in the hole.

What means "surface of the pull"? Pulling is not a substance,
and it doesn't have a surface.

I am afraid the discussion goes directly to the second law of
thermodynamics

I see no reason to think the 2nd law is involved.

In particular, repeat the experiment with liquid helium
instead of water. Cool it to a few millikelvin. Dielectric
effects will be essentially independent of temperature over
a wide range.

a topic I hate because it always generates personal
attacks but never science.

Never?

I'm disappointed to learn that. I always thought thermodynamics
was a branch of science.

Is
it justified to identify the dielectric constant that one places in the
Coulomb law, for two charges immersed in a liquid dielectric, with the
dielectric constant participating in the expression for the voltage of a
capacitor with a box filled with the same liquid dielectric between the
plates?

I can't parse that sentence. The word "with" occurs too many times.

If Panofsky's pressure does exist, the two quantities reflect
entirely different physical events.

There's only one meaning to the term "dielectric constant" that
I've ever run across.