Finding the electric field at point P between two charges

In summary, the electric field at point P, located between charges q1 = -3C and q2 = +4C, can be found by using the equations E = kq/d^2 and Etotal = E1 + E2. The direction of the electric field points to the left of P. The total electric field is given by Etotal = (9E9 * 3)/(2/3x)^2 + (9E9 * 4)/(2/3x)^2, and the distance between the charges is expressed as a function of the charges' separation distance. The charge separation distance is not given, but it can be assumed to be 1 meter.
  • #1
LuckyShamrock
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0

Homework Statement


Find the electric field (both magnitude and direction) at point P located between the charges q1 = -3C and q2 = +4C. Point P is 1/3 of the charges' separation distance from q1 and 2/3 of the charges' separation distance from q2.

Homework Equations


E = kq/d^2
Etotal = E1 + E2

The Attempt at a Solution


I am able to infer that the direction of the electric field points to the left of P. I also know that, due to the above equations, Etotal = (9E9 * 3)/(2/3x)^2 + (9E9 * 4)/(2/3x)^2 therefore Etotal = 3.24E11/x^2

However, I am having trouble finding the distance between the charges q1 and q2. Is there a point between q1 and q2 where the electric field is zero that I can set kq1/d^2 equal to kq2/d^2? I would appreciate any help finding the distance between the two given point charges.
 
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  • #2
The charge separation must be given, possibility is that you missed this information somehow or else the answer is to be expressed as a function of charges distance.
 
  • #3
If it isn't given, I would assume that it is 1 meter.
 
  • #4
Thank you for the help. I emailed my professor, and he confirmed that the answer will be expressed as a function of the charges' separation distance.
 

1. What is the formula for finding the electric field at point P between two charges?

The formula for finding the electric field at point P between two charges is E = kQ/(r^2), where E is the electric field, k is the Coulomb's constant (9x10^9 Nm^2/C^2), Q is the magnitude of the charge, and r is the distance between the two charges.

2. How do you determine the direction of the electric field at point P?

The direction of the electric field at point P is determined by the direction of the force that a positive test charge would experience if placed at that point. It is always in the direction of the force that the test charge would experience.

3. Can the electric field at point P ever be zero?

Yes, the electric field at point P can be zero if the two charges are equal in magnitude and opposite in sign, and are placed at equal distances from point P.

4. What is the unit of measurement for electric field?

The unit of measurement for electric field is newtons per coulomb (N/C) in SI units. In CGS units, it is measured in dynes per statcoulomb (dyn/sc).

5. How does the distance between the two charges affect the electric field at point P?

The electric field at point P is inversely proportional to the square of the distance between the two charges. This means that as the distance increases, the electric field decreases and vice versa.

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