Electric fields problem [closed]

Why is this the case..

I would have thought it would have followed the E field?

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Just remember: "electrons swim upstream" –  Alfred Centauri Jun 19 '13 at 20:34
after which, they are inevitably all eaten by bears –  Jim Jun 19 '13 at 20:37
@Jim I should flag that comment for being funny :P On topic though: take a look at the Lorentz force wikipedia page and keep in mind that the charge $q = -e$ of an electron is negative. Edit: I see that I completely missed the fact that there was already a good answer to your question. You might want to accept that answer if it cleared up your confusion. ;) –  Wouter Jun 19 '13 at 20:54