Electric field at a point charge

[SchruteBucks]

I had a question (very similar to this) for homework a few days ago, which was basically: In which arrangement will the electric field at the leftmost point be largest and in which will it be the smallest?


A.
(+)-------(+)


B.
--------(+)-------(+)


or


C.
----(+)---(+)

I assumed it would be A since the point charge is AT the leftmost point, and through the method that acts like there is a positive charge at a point to estimate the direction and magnitude of the electric field, I got the magnitude of the electric field at that point to be infinite since it is at the same point as the charge. (r² in denominator becomes zero) What am I doing wrong?

 

[JHamm]

You didn't do anything wrong, as you move infinitely close to a charge the electric field goes to infinity.

 

[netgypsy]

point charge

 

[SchruteBucks]

Thanks for the feedback, VERY much appreciated! Wish me luck as I go try to argue for some points back on my homework then. It's usually pretty difficult to argue physics with a guy who has a Ph.D. in the subject though...and actually knows what he's talking about :|

 

[netgypsy]

Go got it. I was so renown for arguing for points, once my professor gave me some I didn't even deserve. But then he had ripped me off on the last test so we were even.