
#1
Nov107, 01:45 PM

P: 2

1. The problem statement, all variables and given/known data
Two point charges of 2.5 µC and 6.0 µC lying along the x axis are 1.0 m apart. Locate the point (other than infinity) at which the total electric field is zero. 2. Relevant equations I was thinking: E=F/q and F=K (Q x q)/d^2 But I'm not quite sure how to use them. 3. The attempt at a solution Using the second equation I found F to be .135. But I don't think that's right, and then when plugging that into the E=F/q. E would have to be zero, since I'm trying to find where the total electric field is zero? Then there's no solutions other than infinity, are there? And what exactly is q in the first equation. I really have no idea what's going on here. 



#2
Nov107, 02:01 PM

P: 792

If the electric field is zero, is it the case that the force is also zero? So find the point(s) where the net electric force or field is zero.




#3
Nov107, 03:43 PM

P: 2

I found an example online and I think I substituted the right numbers in for this problem, is this how it would be solved? (I didn't understand the equation below and where it came from: KQ/x²2.4KQ/(x+1.00)²)
Enet=Esub1 + Esub2 = KQ/x²2.4KQ/(x+1.00)² KQ/x²2.4KQ/(x+1.00)² The Ks and Qs cancel out leaving: 1/x² = 2.4/(x+1.00)² And then get it into a quadratic: 1.4x²  2x 1=0 And find it to be 1.82 m to the left of charge Q. I ignored the other root, .39m because that would be between the two charges where the fields cannot cancel out. Am I on the right track? 


Register to reply 
Related Discussions  
1.) Net electric field and 2.) Maximum electric field from centre of a ring  Introductory Physics Homework  7  
Electric field in a dielectric in terms of the electric field in the vacuum  Introductory Physics Homework  0  
Where is the Electric Field Equal to Zero?  Introductory Physics Homework  40  
[SOLVED] What is the electric field very close to an electron, and what is the total  General Physics  0  
Why is the magnitude of the electric field equal in all cases?  Introductory Physics Homework  7 