AL 2題 electric fields 急救命

garycoolman

1. the electrics potential energyof a system of charges at infinitely large distances from one
another is taken to be zero. waht is the clectric potential energy stored in a systen of four charges, each +1C, placed at the vertices of a square with length of side 1m?



2. a uniformly charged wire has the form of a circular loop of radius b.
p1 and p2 are two points on the axis of the loop.
p1 is at a distance b  from the loop centre and p2 is at a distance 2b from the loop centre .
at p1,p2, the potrntials are v1,v2 respectively .what is the 數值 of  v2/v1 ?(v2 over  v1)

答到加good

garycoolman

e=permittivity of vaccum

answer 1.    (4+root2)/4pi e
           2. root2/root5

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