[pstricks] pst-electricfield

[Doris Behrendt]

hi all,

I have found some errors (concerning physics) in the package:

1.) rogue field lines: the horizontal line in picture 1 is NOT a  
normal field line, but a so called rogue field line: if you change  
posArrow=.3 to posArrow=.4, the direction of the arrow will change;  
this is physically the right behaviour, but problematic when one  
thinks of large distances where the arrow must point to the left, not  
right;

2.) the number of lines emanating from a positive charge (or  
terminating on a negative charge) is proportional to the magnitude of  
the charge [tipler/mosca, p.712], so if you look at picture no.2 and  
count the lines emanating the double positive charge, you get 16;  
following the above proportionality, there must be 8 lines terminating  
in the right charge (negative and half the magnitude of the right  
one), but there are only 7;

3.) the lines emanating from (or terminating on) an isolated charge  
are drawn uniformly spaced as they emanate (or terminate) [tipler  
again], so if you look at the pictures no.3 or no.4, this is not the  
case;

??

doris