Timeline for Why is the electric potential at a distance of $R$ from a point charge $q$ equal to $\frac{-q}{4\pi\varepsilon_0 R}$
Current License: CC BY-SA 4.0
6 events
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| Jul 3, 2020 at 9:12 | vote | accept | Rajdeep Sindhu | ||
| Jul 3, 2020 at 9:08 | comment | added | Puk | As I said, there should be no minus sign in the equation for the potential. | |
| Jul 3, 2020 at 9:07 | comment | added | Rajdeep Sindhu | But the formula shouldn't be different, right? | |
| Jul 3, 2020 at 9:06 | comment | added | Puk | That definition is correct if "internal force" means the force applied on the unit charge by the electric field (i.e. the existing charges). For a single positive charge, this work would be negative, so the potential would be positive. If there is no mistake in the book, you might be quoting the equation out of context. | |
| Jul 3, 2020 at 9:00 | comment | added | Rajdeep Sindhu |
It says that the negative of the work done by internal force in bringing a unit positive charge from infinity to that point is the electric potential at that point. I don't quite get what that means though. But, I saw a lecture of Professor Walter Lewin and used another book, and just as you say, the negative symbol was not there. It has the negative sign in the formula for electric potential energy too. It just mentions that the electric potential energy will be negative of work done in bringing test charge from infinity to that point keeping the other charge fixed but doesn't tell why...
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| Jul 3, 2020 at 8:56 | history | answered | Puk | CC BY-SA 4.0 |