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pvalev wrote:The
V_metal = V_vacuum / D /1/
where D is the dielectric constant of the intervening material.
theinspection of the physical picture or an experiment would convince
them that V_m is practically zero, i.e. D is extremely great. But
then they may find that, in accordance with Coulomb's law
F = k(q1*q2)/Dr^2 /2/
the attraction between the plates has also vanished. (After all,
totallyplates can be ragarded as two charged bodies that obey Coulomb's
law). But this would be a wrong conclusion - the same physical
picture that showed vanishing of the voltage now shows INCREASE of
the force of attraction:
What is the justification of your last sentence? If the metal
fills the region between the plates, it shorts out the capacitor.There
must be an insulating gap next to the plates. Let's assume it'svacuum
for simplicity. The extremely low field in the metal is due to thethe
canceling of the original field before the metal is inserted by the
induced field produced in the metal because of its induced surface
charges. The field in the vacuum gap between the inserted metal and
plates is still the same as before the metal was inserted.