# 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.

#### Attachments

Last edited:

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.

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Thanks, turns out it was just my conversion.