- #1
GDGirl
- 50
- 0
Homework Statement
A charge Q1 = 0.0306 μC is located a distance d = 4.17 cm to the left of another charge Q2 = - 0.0206 μC.
a. At what point along the line joining the charges is the electric field zero? Give your answer as the distance x from the charge Q2, positive if the point lies to the right of Q2 and negative if to the left.
HELP: First figure out the approximate region in which the third charge can be placed so that the electric forces from the first two charges will balance.
HELP: Set the electric fields from Q1 and Q2 equal at position x--you will have to solve a quadratic equation to find x.
Homework Equations
E=kQ/r2
Quadratic equation
The Attempt at a Solution
First I solved the for the electric field of both charges, but I'm not sure if that is relevant to my problem or not.
Then, I followed the Help's advice, and set my two equations equal to each other:
-((8.99x109)(.0206x10-6))/(.0417-x)2=((8.99x109)(.0306x10-6))/x2
I ended up with x = 51.641 or -3.643. Neither is correct as confirmed both by my plugging in the numbers and checking, and submitting the answers in my answer box. :/
I'm confused about whether x should be squared or not, I'm pretty sure it should be. If the E-field of my negative charge should be negative or not... And if i should be doing .0417-x as the distance in said E-field...