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Re: [Phys-L] Field Lines and charges



Ok, but aren't those field lines the continuation of the ones which are in a
direct line between the two charges? Of course these lines are infinitely
thin so to speak. After all field lines are generated by following the
direction of the force and in the lines of symmetry between the charges
there are lines coming from the charges and terminating with zero force in
the center, and then lines coming out from this region. Of course you can
not pick which line coming out is associated with the line going in. So the
two singular lines going to the center are associated with the two singular
lines coming from the center.

John M. Clement
Houston, TX


But these particular lines are not *beginning* on a positive
point charge. The termination is not the point of the posting
(I should not have mentioned it - just confuses the issue).

Bob at PC


However assuming that the charge of the universe is zero, they would
eventually terminate or start on a charge.

John M. Clement
Houston, TX


Consider a configuration of two point charges of value
+q, one placed
on the x axis of a standard x-y-z coordinate system at +a and the
other at -a. Now look at the electric field vectors - specifically
along the y axis.

For any position along the positive y axis the field
vector points in
the positive y direction. The field magnitude is zero at
y = 0, and as
y increases, grows and forms a maximum at y = 0.707 a, and then
gradually goes to zero as y increases further in value. One could
trace a field line starting at y=0, x=0 and follow it along the
positive y axis to positive infinity.

For any position along the negative y axis the field
vector points in
the negative y direction. The field magnitude is zero at
y = 0, and as
y decreases, grows and forms a maximum at y = -0.707 a, and then
gradually goes to zero as y increases further in value. One could
trace a field line starting at y=0, x=0 and follow it along the
negative y axis to negative infinity.

Here is a pair of field lines that do not follow the
usual maxim of
starting and stopping on a charge.

Bob at PC



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