Physics
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 r2
b) infinite line ... it goes like r1
c) electric dipole ... it goes like r3
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)