Here's my problem:(adsbygoogle = window.adsbygoogle || []).push({});

Three 10-cm-long rods form an equilateral triangle. Two of the rods are charged to + 10 nC, the third to -10 nC. What is the electric field strength at the center of the triangle?

Answer in back of book: 1.08 * 10^5 N/C

By looking at the corresponding section, it gives the formula for the electric field strength in the plane that bisects a charged rod as:

Q/(4*pi*e_0*r*sqrt(r^2 + (L/2)^2)),

where e_0 is given to be 8.85*10^-12.

I thought that you would add the vertical and horizontal components of the 3 electric fields in the center due to each rod to get the net electric field. After some calculations, I get that the final answer should be 2 times the formula I gave above, but this does not give me the correct answer. What am I doing wrong? Please respond, thanks!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Electric Fields and rods

**Physics Forums | Science Articles, Homework Help, Discussion**