- . . . potential.1
- In
case this is not self-evident,
remember that the force
on a charge q is given by
= q,
where
is the electric field,
measured in N/C or V/m. If we move a particle
a distance d
under the influence of a force ,
that force does
d
work on the particle
- which appears as kinetic energy!
If we move a charge q=e a distance x
parallel to a constant electric field E,
the work done is e E x,
or (e)(E [V/m])(x [m]) = eV. After all, the reason
is called the ``electric potential'' is that
when multiplied by q it gives the potential energy of the
charge in the electric field.
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- . . . kilowatt-hour?2
- Recall
that watts (W) are a unit of
power (energy per unit time) equal to
joules per second: 1 W
1 J/s.
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- . . . drawings,3
- For
this and the next question, the final result is well known
and the full derivation can be found in any textbook;
however, you will not really own GAUSS' LAW
until you have expressed and used it your own way.
This is true for almost everything, but GAUSS' LAW
is so important (and so simple!) that you should not
miss this chance to make it yours.
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- . . .
WOOPS!4
- We forgot to hand out last week's assignment
on Thermodynamics! These were the problems; see if you can find
time to do them over then next few weeks - no deadline, but
it would be wise to have a look before the Physics Midterm.
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