Where the total electric field is equal to zero?

In summary, the problem involves two point charges on the x-axis and the goal is to find a point where the total electric field is zero. The equations used are F=K(Qxq)/d^2 and E=F/q, but there is confusion about how to use them. The attempt at a solution involved finding the net electric force using the second equation and then using the example equation to solve for the point where the electric field is zero. The final answer was 1.82 m to the left of charge Q.
  • #1
barrett
2
0

Homework Statement


Two point charges of -2.5 µC and 6.0 µC lying along the x-axis are 1.0 m apart. Locate the point (other than infinity) at which the total electric field is zero.

Homework Equations


I was thinking: E=F/q
and
F=K (Q x q)/d^2
But I'm not quite sure how to use them.



The Attempt at a Solution


Using the second equation I found F to be -.135. But I don't think that's right, and then when plugging that into the E=F/q. E would have to be zero, since I'm trying to find where the total electric field is zero? Then there's no solutions other than infinity, are there? And what exactly is q in the first equation. I really have no idea what's going on here.
 
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  • #2
If the electric field is zero, is it the case that the force is also zero? So find the point(s) where the net electric force or field is zero.
 
  • #3
I found an example online and I think I substituted the right numbers in for this problem, is this how it would be solved? (I didn't understand the equation below and where it came from: KQ/x²-2.4KQ/(x+1.00)²)

Enet=Esub1 + Esub2 = KQ/x²-2.4KQ/(x+1.00)²
KQ/x²-2.4KQ/(x+1.00)²

The Ks and Qs cancel out leaving:
1/x² = 2.4/(x+1.00)²

And then get it into a quadratic:
1.4x² - 2x -1=0

And find it to be 1.82 m to the left of charge Q. I ignored the other root, -.39m because that would be between the two charges where the fields cannot cancel out.
Am I on the right track?
 

1. What is the concept of total electric field being equal to zero?

The concept of total electric field being equal to zero refers to a point in space where the sum of all electric fields from different sources is equal to zero. This means that the forces acting on a charged particle at that point will be balanced, resulting in no net movement.

2. What is the significance of finding a point where the total electric field is zero?

Finding a point where the total electric field is zero is significant because it can help us understand the behavior of electric fields in a given space. It can also be used to determine the position of electric charges or to locate regions of equilibrium in a system.

3. How is the total electric field calculated?

The total electric field at a point is calculated by vectorially adding all the individual electric fields at that point. This can be done using the principle of superposition, where each individual field is determined by the charge and distance from that point.

4. Can the total electric field ever be zero in a practical scenario?

Yes, the total electric field can be equal to zero in a practical scenario. This can occur when the magnitude and direction of the electric fields from different sources are perfectly balanced, resulting in a net electric field of zero at that point.

5. How does the total electric field being zero relate to electric potential?

The total electric field being zero at a point also means that the electric potential at that point is constant. This is because the electric potential is directly proportional to the electric field, and if the field is zero, the potential will also be zero. This concept is known as equipotentiality.

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