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Physics
Classical Physics
Electromagnetism
Confusion about electric potential
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[QUOTE="Nugatory, post: 5486533, member: 382138"] If you actually calculate out the integration, you'll find that if the force at every point goes as ##1/r^2## the potential at any point goes as ##1/r##. The change in potential energy is the difference between the potential at the starting point and the potential at the ending point. It's also what you get by summing (as an integral) the change in the potential across each infinitesimal step along the path from starting point to ending point. Do not confuse the change in the potential between two points separated by a distance ##r## and the potential at a point at a distance ##r## from the positive charge. The best way to keep it all straight is to use different letters for the different quantities in the problem: ##R_0##: the distance of the starting point from the central charge. ##R_1##: the distance of the ending point from the central charge ##\Delta{R}=R_1-R_0##: the distance the negative charge is displaced ##r##: a label for an arbitrary distance from the central charge. The potential energy at a point at a distance ##r## from the central charge is ##-KQ/r## and the attractive force is ##KQ/r^2##. The potential energy gain when I move the charge a distance ##\Delta{R}## from the starting point at ##R_0## to the ending point at ##R_1## is ##KQ(1/R_1-1/R_0##. [/QUOTE]
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Physics
Classical Physics
Electromagnetism
Confusion about electric potential
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