I recently posted an answer to

(1) Why are magnetic fields only produced by moving charges?

which was marked as a duplicate of

(2) No magnetic field from a static charge - Is there a simple physical argument to show why?

I don't think that (2) has a really satisfactory answer. In any case, I think that my answer to (1) would contribute non-trivially to (2). What are the physics.SE norms/policies about re-posting my answer from (1) as a response to (2)?

  • 2
    $\begingroup$ Good question, I'm not sure offhand. The first idea that comes to mind is delete your answer from (1) and post it to (2), but I couldn't say if that is the actual recommended practice. I'll post it as an answer if nobody offers anything better. $\endgroup$
    – David Z
    Aug 28, 2013 at 21:32
  • 2
    $\begingroup$ Even if the answer has earned me points, I usually just delete it and copy the content into the earlier question. We even have a special "Disciplined" badge that you can get for doing this! It's not hard to rack up points on SE. What's annoying is when the original question is poorly written compared to the duplicate, or when the best answer is the answer someone else wrote for the duplicate, and it's already got a lot of up-votes so I can't really ask them to delete and copy. $\endgroup$
    – user4552
    Sep 2, 2013 at 22:06
  • $\begingroup$ Deleting an answer also deletes any comments on it. $\endgroup$
    – user4552
    Sep 2, 2013 at 22:13

2 Answers 2


If a merge is not in order (and I don't think that one is), then re-using your own material is reasonable and proper. I hesitate to suggest verbatim coping of an answer, because most of the time we treat that as a sign of possible abuse.

Does posting a substantially similar answer that has refocused for the slightly different emphasis of the two question appeal?

DavdZ's suggesting in the comments to delete on the "duplicate" is also very reasonable, especially if you haven't accumulated points for that answer yet.

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    $\begingroup$ +1: Yeah this sounds reasonable. I probably will end up modifying my answer a bit to be more appropriate for the duplicate question, and then re-posting it. Some of the bulk of the material will probably be rather close to verbatim however; hopefully this will not be considered abuse. $\endgroup$ Aug 28, 2013 at 21:43
  • $\begingroup$ The problem is that there is dup link to the original question, but not the reverse link. How the SO deal with this kind of problem. $\endgroup$
    – unsym
    Aug 29, 2013 at 1:06
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    $\begingroup$ It is linked in the sidebar. But the "original" question (not necessarily the first one asked, but the one that is not closed) is meant to be the canonical version where all the answers are collected, so it is less necessary to have links pointing from that one to the others. $\endgroup$
    – David Z
    Aug 29, 2013 at 23:37
  • $\begingroup$ @DavidZ It's precisely the fact that the original question is supposed to be the canonical one that motivates me to re-post in a slightly modified form; that's what I ended up doing. $\endgroup$ Aug 29, 2013 at 23:58

Maybe you should give a summary of and a link to your answer to the duplicate question.


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