The forces between electrical charges have an electrical potential energy associated with this force. The total ME = KE gravitational PE elastic PE electric PE.

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The forces between electrical charges have an
electrical potential energy associated with this
force. The total ME KE gravitational PE
elastic PE electric PE.
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If a positive charge is moved in a uniform
electric field in the same direction as the
field, there is a change (decrease) in the
electric potential energy of that
charge.?PEelectric -qE?d
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It is the difference in potential that is
important. If we set the initial d to be zero,
thenPEelectric -qEdThis is only true for a
uniform field.
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d is the magnitude of displacement in the
direction of the electric field. Perpendicular
motion does not change the PE.
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If there are two charges, another equation is
needed.PEelectric kq1q2/rThe reference point
is infinity. The ?PEelectric is for like
charges and - for unlike charges.
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What is the electric potential energy between two
electrons that are two meters apart?
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The electrical potential energy associated with
an electron and proton is -4.35 x 10-18 J. What
is the distance between these two charges?
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PEelectric depends on the charge. A more
practical concept is electric potential
PEelectric/q V.
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Electric potential is independent of charge. The
reference point for electric potential is
arbitrary, only the difference in potential is
important. Therefore?V ?PEelectric/qThe unit
is the volt, which is equal to one joule per
coulomb.
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As a one coulomb charge moves through a potential
difference of one volt it gains (or loses) one
joule of energy.
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Remember PEelectric -qEd and?V
?PEelectric/q.So ?V ?(-qEd/q) or ?V -?Ed
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Voltage difference between a point at infinity
and a point near a point charge ?V kq/r
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These potentials are scalars, not vectors there
is no direction involved.
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A 5.0 mC point charge is at the origin, and a
point charge of -2.0 mC is on the x-axis at
(3.0m,0.0m). Find the total potential difference
resulting from these charges between a point
with coordinates (0.0m, 4.0m) and a point
infinitely far away.
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A battery does work to move a charge. As a charge
moves through a 12V battery its potential is
raised by 12V. If it is a 1 coulomb charge its
energy is raised by 12 joules.
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