- #1
natalie.*
- 8
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Hi, this is my first time posting on the forums, so if I make any mistakes, I'm sorry.
This question has already been started here:
https://www.physicsforums.com/showthread.php?t=449070
but they never got to part (b).
PART A
A -10.1 nC point charge and a +18.9 nC point charge are 13.8 cm apart on the x-axis. What is the electric potential at the point on the x-axis where the electric field is zero?
I was able to figure this much out.
PART B
b) What is the magnitude of the electric field at the two points on the x-axis where the electric potential is zero? (Input your answers in order of increasing distance from the negative point charge)
[tex]q_{1}=-10.1 \times 10^{-9} C[/tex]
[tex]q_{2}=18.9 \times 10^{-9} C[/tex]
[tex]d=0.138 m[/tex]
[tex]r_{2}=d-r_{1}[/tex]
[tex]r_{1}=r_{1}[/tex]
[tex]V_{net}=\frac{Kq_{1}}{r_{1}}+\frac{Kq_{2}}{r_{2}}[/tex]
Simplified down to...
[tex]r_{1}=\frac{q_{1}d}{q_{1}-q_{2}}[/tex]
but this only finds me ONE point where the electric potential is zero. I'm supposed to end up with two...
I can't think of any other way to look at it, or get a quadratic out of it.
Where did I go wrong?
Homework Statement
This question has already been started here:
https://www.physicsforums.com/showthread.php?t=449070
but they never got to part (b).
PART A
A -10.1 nC point charge and a +18.9 nC point charge are 13.8 cm apart on the x-axis. What is the electric potential at the point on the x-axis where the electric field is zero?
I was able to figure this much out.
PART B
b) What is the magnitude of the electric field at the two points on the x-axis where the electric potential is zero? (Input your answers in order of increasing distance from the negative point charge)
[tex]q_{1}=-10.1 \times 10^{-9} C[/tex]
[tex]q_{2}=18.9 \times 10^{-9} C[/tex]
[tex]d=0.138 m[/tex]
[tex]r_{2}=d-r_{1}[/tex]
[tex]r_{1}=r_{1}[/tex]
Homework Equations
[tex]V_{net}=\frac{Kq_{1}}{r_{1}}+\frac{Kq_{2}}{r_{2}}[/tex]
The Attempt at a Solution
Simplified down to...
[tex]r_{1}=\frac{q_{1}d}{q_{1}-q_{2}}[/tex]
but this only finds me ONE point where the electric potential is zero. I'm supposed to end up with two...
I can't think of any other way to look at it, or get a quadratic out of it.
Where did I go wrong?