Here we have an apple
that is at a height “h”
above the
Earth’s surface.
The apple has a
potential energy
equal to
Anywhere along the
dotted line the apple has
the same height,
therefore the same
potential energy.
Anywhere along the
dotted line the apple has
the same height,
therefore the same
potential energy.
Anywhere along the
dotted line the apple has
the same height,
therefore the same
potential energy.
This line that has the
same potential is called
an
line.
This line that has the
same potential is called
an
line.
For any object there is an
infinite number
of
lines.
Here we show
some
of the different
lines.
If we moved the apple
along one of
these
lines
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
there would be
no change
in potential energy
therefore
no work would be done.
Once again,
there was NO WORK done
in moving the apple
along the
from point A to point B.
We also know that
if we raise an apple
above the Earth
and let it go,
it will fall.
We also know that
if we raise an apple
above the Earth
and let it go,
it will fall.
We also know that
if we raise an apple
above the Earth
and let it go,
it will fall.
We also know that
if we raise an apple
above the Earth
and let it go,
it will fall.
We also know that
if we raise an apple
above the Earth
and let it go,
it will fall.
We also know that
if we raise an apple
above the Earth
and let it go,
it will fall.
The direction that the
apple accelerates tells us
the direction of the
gravitational force.
The direction of the
gravitational force
and the pattern of
equilpotential lines
give us a view
of the
.
By
Richard J. Terwilliger
around
the Earth.
means that there will be
a gravitational force on
an object if it is
placed in the field.
Could this model
also work
with
And how would
we deal with
two different net charges?
Let’s start with
an object that has a
NET NEGATIVE
charge.
Placing a “test” charge in
the vicinity of this net negative
charge and noticing if it
experiences a force will
tell us if there is an
Electric Field
around the charge.
It will also tell us
the direction
of the
Electric Field.
The test charge is
always
defined as
Therefore the test charge
has a force acting on it
the net negative
charge.
This is the direction
of the
Moving the test charge
around the net negative
and plotting the
direction of the force
will show us the field
surrounding the charge.
This positive test charge
if free to move
will “fall” towards
the net negative charge.
This positive test charge
if free to move
will “fall” towards
the net negative charge.
The positive test charge
has no
potential energy
at this point.
To pull the positive test
charge away from the
negative we must do
work on the positive
test charge.
This work
is equal to
the potential energy
at that point.
So similar to the
equipotentials
surrounding the Earth,
we have equal potentials
surrounding the
net negative charge.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
By
Richard J. Terwilliger
If the charge moves
along the equipotential
there is no work done.
By
Richard J. Terwilliger
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
By
Richard J. Terwilliger
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
If the charge moves
along the equipotential
there is no work done.
We now know the
direction of the force
and the
pattern of equipotentials
around the
net negative charge.
Notice the
lines of force
are at
right angles
to the
equipotential lines.
o
90
We can now predict the
electric lines of force
and the equipotential lines
around a
charge.
A positive test charge
placed near the
net positive charge will
experience a force
outward.
Therefore the electric field
surrounding the net
positive radiates out
away from the
positive.
And the equipotential lines
must cross these force lines
at right angles forming
concentric circles.
Notice the force lines
never cross each other
and the equipotential lines
never cross.
So we now know what
the fields look like around
either a positive
or negative charge
What would the electric
field lines and the
equipotential lines look like
around two charges?
One negative
and
one positive.
First we place our
positive test charge
in the field and determine the
direction of the force
on the test charge.
The test charge is
repelled away from positive
and attracted toward
the negative.
Now move the test charge
to a new position and
determine the direction
of the force.
Keep moving the test
charge and
determine the direction
of the force at each
new position.
Keep moving the test
charge and
determine the direction
of the force at each
new position.
If we place the test charge
at the position shown,
The test charge will
experience a large force
pushing it away from
the positive charge and
A very small force
pulling it towards
the negative charge.
The electric field,
at this point,
would be the resultant
of these two forces.
Move the test charge
and again find the resultant.
Here the test charge is
further away from the
positive charge so the
force is smaller.
Move the test charge
and again find the
resultant force.
Keep repeating until you
have the pattern for the
electric field line,
the line of force.
Once more.
Connecting all of
these arrows gives us
the electric field line.
From here we can
finish the pattern.
Now draw in the
Remember, they never cross
each other and must
cross the force lines
at right angles.
What does the
Electric Force lines and
Equipotential lines look like
between parallel plate
charges?
What does the
Electric Force lines and
Equipotential lines look like
between parallel plate
charges?
Let’s check it out!
First we’ll start with two
parallel plates.
Next we’ll charge one plate
net negative and the other
plate net positive.
To determine the direction
of the electric field we’ll
place the test charge
between the plates.
Remember the test
charge?
Is the test charge
positive or negative?
CLICK on YOUR
ANSWER
A positive charge placed
between the two parallel
plates
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
will be forced away from
the positive plate and
towards the negative plate.
Therefore the
electric field direction between two
parallel charged plates is
away from the positive plate
and towards the negative plate.
And the equipotential lines are
perpendicular to the force lines.