GREPhysics.NET: GR0177 #7

GR0177 #7

Problem

GREPhysics.NET Official Solution

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Electromagnetism $\Rightarrow$ }Field Lines

Since one has same polarity magnet ends at the same side, one can immediately cancel out choices (A) and (D). They would repel each other, and thus the field-lines would not be pointing towards each other. Since there are no such things as magnetic monopoles, one cannot have choice (C), as that would imply a non-zero divergence in the magnetic field. Choice (D) would work if there were a current through the magnets, but there's not. Choice (B) remains. It makes sense since the magnetic charges should repel each other, and thus the field lines should point away showing the repulsion.

Alternate Solutions

jmason86 2009-07-13 20:07:12	Or if you've ever done this experiment in elementary school... just remember what the iron fillings did. Reply to this comment
Ning Bao 2008-02-01 05:39:05	There must be no field in right between the two magnets because a particle put there would be in an unstable equilibrium -> B or E. E is wrong because you don't expect the fields to only be depended on distance away from a mingle pole. Reply to this comment

Comments

jmason86 2009-07-13 20:07:12	Or if you've ever done this experiment in elementary school... just remember what the iron fillings did. Reply to this comment
Ning Bao 2008-02-01 05:39:05	There must be no field in right between the two magnets because a particle put there would be in an unstable equilibrium -> B or E. E is wrong because you don't expect the fields to only be depended on distance away from a mingle pole. Reply to this comment
OrbitGirl 2007-10-03 11:00:34	Choice (D) would work if there were a current through the magnets... I think you meant (E). Reply to this comment
cailh 2006-10-28 06:34:51	Reply to this comment

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