Electric Field and Potential on a Line with Opposite Charges

[silver_gry]

Homework Statement

A positive charge of +q is located 3.00m to the left if a negative charge -q2. The charges have different magnitudes. On the line through the charges, the net electric field is zero at a spot 1.00m to the right of the negative charge. On this line there are also two spots where the potential is zero. Locate these 2 spots relative to the negative charge.

Homework Equations

I don't know which equation I should use to start with. I really need help with this question.

The Attempt at a Solution

 

[Delphi51]

At the point where E = 0, the E field due to the positive charge is equal (and opposite) to the E field due to the negative charge. Write this, replace each E with the formula for E, put in the numbers for the distance. You will end up with Q1 = a number times Q2.

Now pick a point x on the line through the charges. Say, x meters to the right of Q1. Write the expression for the potential there - the sum of the potentials due to each charge. Use the multiple of Q1 in place of Q2 so the Q1 cancels out in this equation. You should be able to solve it and find x.

 

[nlightner]

I would first identify the given information and variables in the problem. The given information includes the presence of two opposite charges (+q and -q2) on a line, with the positive charge located 3.00m to the left of the negative charge. The problem also states that on this line, there is a point 1.00m to the right of the negative charge where the net electric field is zero, and two points where the potential is also zero.

To solve this problem, I would use the equation for electric field: E = kq/r^2, where k is the Coulomb's constant, q is the magnitude of the charge, and r is the distance between the charges. Using this equation, I can calculate the electric field at the point 1.00m to the right of the negative charge, and then use it to determine the magnitude of the positive charge q.

Next, I would use the equation for electric potential: V = kq/r, where V is the potential, k is the Coulomb's constant, q is the magnitude of the charge, and r is the distance between the charges. Using this equation, I can calculate the potential at the two points where it is zero, and then use it to determine the distance between these points and the negative charge, as well as the magnitude of the positive charge q.

In summary, as a scientist, I would approach this problem by using the equations for electric field and potential to calculate the unknown variables and solve for the two points where the potential is zero relative to the negative charge. This would allow me to fully understand the behavior of the electric field and potential on a line with opposite charges.