# Interaction of an electric field of infinite length [closed]

Question: In a system which prodivides an electric field of an infinite length, if another electric field or particle interacts with it at a certain point, will there be a change at a point infinitely away?

the reason I believe it will effect that point is because of the behavior which is observed in simple electric circuits. When the battery is turned on, a wave propagates within the circuit to determine the current of the sytem.At this point, the current is inhomogeneous withing the circuit(but this dissapears almost at the speed of light). Let's suppose there are also resistances of different resistivity connected to this circuit. The electrons within the circuit are a part of the same system, thus, if one slows down, the rest will slow down too. The "voltage drop", at this point affects the whole system at the same time. The loss of potential is calculated in the initial turn on, and the current is thus established. The reason why this drop of voltage equals to the V of the battery is because all is calculated according to this wave which is launched from the battery.

Question: In a system which provides an electric field of an infinite length, if another electric field or particle interacts with it at a certain point, will there be a change at a point infinitely away?

Good question. I think the answer is maybe yes or maybe no. It depends on whether the source of other electric field that interacts with the system is due to charge of the same or different polarity.

If the sources involve the same polarity charge, the fields should reinforce each other and increase the field strength at infinity,

If the sources are of opposite polarity there should be a reduction in field strength at infinity.

Finally if the sources are of opposite polarity and of the same magnitude, the field strength should appear to be zero at infinity as the overall charge is neutral.

Hope this helps.

First of all, note that the electric field generated by any finite electric charge distribution must go to zero at infinite distances. We can only have nonzero fields at infinite distances if we consider a theoretical infinite charge distribution. For these theoretical constructions, in principle, we could have the total resultant electric field changing (by the principle of superposition), even at infinite distances, if we were to add some other similar sources. However, considering only finite sources (i.e, real world, physical sources), the resultant electric field will be zero at infinite distances from the sources.

Regarding the circuit: the propagation of the electromagnetic wave is indeed very fast, but certainly none of the microscopic phenomena you tried to describe occur instantly. In fact, you could try to measure the transient response as you turn the battery on, and observe that it takes some time for the wave to reach each element of the circuit (although I think this is probably going to be difficult).