posted by Julia .
Recall that for a finite rod of length L and total charge Q, the electric field for a point located a perpendicular distance r from the middle of the rod has a magnitude given by:
Consider the limit of large distances, where a finite charged rod is observed at a distance that is very large when compared to the length of the rod.
In this situation, the electric field best resembled that of a ...
a)point charge ... it goes like r-2
b) infinite line ... it goes like r-1
c) electric dipole ... it goes like r-3
d) infinite plane ... it is constant
none of the above ... it is zero
The finite rod of length L and charge Q looks more like a point source as the observer gets farther way.
The answer is a)