# Find the magnitude and the direction of the electric field at the thir

## Homework Statement

Two point charges are placed at two of the corners of a triangle as shown in the figure. (Take q1 = -11.3 μC, and q2 = 15.4 μC.) Find the magnitude and the direction of the electric field at the third corner of the triangle. {Correct Answer: 1.07e+07 N/C at 71.2 degrees above the -x-axis}

## Homework Equations

F = ((1)/(4πε0))(q1*q2/r^2)

## The Attempt at a Solution

Attached files. What am i doing wrong? I can't seem to get the correct answer.

Last edited:

## Answers and Replies

TSny
Homework Helper
Gold Member
Did you convert units correctly? Your answers appear to be off by some factors of 10.

Is Ey from q1 positive or negative? [Edited]

Hmm I don't know how I got a negative. But either way when I solve for the magnitude it'll end up being positive. Which unit should I convert? The μc or cm?

TSny
Homework Helper
Gold Member
Hmm I don't know how I got a negative. But either way when I solve for the magnitude it'll end up being positive.
Yes, but the sign of Ey will affect the answer for the direction angle.
Which unit should I convert? The μc or cm?
Neither μC nor cm is an SI unit.

• 1 person
Thanks, turns out it was just my conversion.