What is the difference between the 2D and 3D electric field and the potential. Why is it that the potential increases when going from the 2D to the 3D representation but the electric field decreases? I understand the equations surrounding this explanation, but why does this happen? Note that here we refer to the 2D case as an infinitely long line of charge extending into and out of the screen. For the 3D case, this is simply a spherical point charge in free space.
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1$\begingroup$ What do you mean by a point charge in 2D space? A line of charge in 3D? $\endgroup$– Roger V.Commented Apr 10, 2020 at 12:53
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$\begingroup$ @Vadim Sorry, In 2D space I refer to it as being an infinite line of charge extending into and out of the screen $\endgroup$– JayPCommented Apr 10, 2020 at 12:59
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$\begingroup$ Point charges in 2D and 3D are different animals. When you say "representation" this suggests that they are the same. $\endgroup$– my2ctsCommented Apr 10, 2020 at 13:02
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$\begingroup$ @my2cts Hopefully that sounds better $\endgroup$– JayPCommented Apr 10, 2020 at 13:05
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$\begingroup$ @Artem Pulemotov Re. "In 2D space I refer to it as being an infinite line of charge extending into and out of the screen" That can not happen since by definition of 2D there is no dimension "extending into and out of the screen". $\endgroup$– user45664Commented Apr 10, 2020 at 18:19
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Be careful when talking about “the potential”. You need to specify where the potential is zero. Keep in mind that the E field determines the rate of change of the potential. Where the field is weaker, the potential changes less rapidly.
