Calculating Electric Field due to two point charges.

In summary, the problem involves two point charges, q1=2.4e-6 C located at (0,0) and q2=-5.7e-6 C located at (3,0), and the task is to calculate the magnitude of the electric field at (0,0). The equation E=kq/r^2 (where k=9e9) is used to calculate the electric field, but there is uncertainty in the problem statement as one of the positions may be incorrect. Additionally, the direction of the electric field and its orientation is also a part of the problem. However, it is not possible to determine the electric field from a point charge at the point charge.
  • #1
Mnemonic
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Homework Statement


Two points charges.

q1=2.4e-6 C is located at (0,0)

q2=-5.7e-6 C is located at (3,0)

I must calculate the magnitude of the Electric field at (0,0)

Homework Equations


E=kq/r^2 ; k=9e9

The Attempt at a Solution


The electric field at (0,0) due to q2=9e9x(-5.7e-6)/3^2 = -5700N/C

Next would be to add the electric field at (0,0) due to q1.
However, I don't know how to calculate the field as distance is r=0 which doesn't work with the formula.

How do I calculate the electric field due to a point charge AT the point charge?
 
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  • #2
You don't. Please quote the problem exactly as stated and not your interpretation of it.
 
  • #3
Orodruin said:
You don't. Please quote the problem exactly as stated and not your interpretation of it.
"Consider a system where a charge -5.7-μC is located at x = 3.0-m, y = 0.0-m and another charge +2.4-μC is located at x = 0.0-m, y=0.0-m. Find the magnitude of the electric field at x = 0.0-m, y = 0.0m. "
 
  • #4
This is very likely a misprint in the problem statement. It is likely that one of the values of the positions is wrong or, if part of a bigger problem, the field at (0,0) from q2 is what is intended.
 
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  • #5
Orodruin said:
This is very likely a misprint in the problem. It is likely that one of the values of the positions is wrong or, if part of a bigger problem, the field at (0,0) from q2 is what is intended.

The next part is :In what direction is this electric field orientated, measured in the normal way (anti-clockwise from the x-axis, which is pointing to the right in the above figure)?

I tried just the field at (0,0) from q2 at got the wrong answer :( Will try and contact my lecturer

To put it simply is it impossible to determine the electric field from a point charge at the point charge?
 
  • #6
Mnemonic said:
To put it simply is it impossible to determine the electric field from a point charge at the point charge?
The answer to this is: NO !
 
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1. How do I calculate the electric field due to two point charges?

To calculate the electric field due to two point charges, you can use the formula E = (k*q1*q2)/r^2, where E is the electric field, k is the Coulomb's constant, q1 and q2 are the magnitudes of the two point charges, and r is the distance between the charges.

2. What unit is used to measure electric field?

The unit used to measure electric field is Newtons per Coulomb (N/C).

3. Can the electric field be negative?

Yes, the electric field can be negative. This indicates that the direction of the electric field is opposite to the direction of the force on a positive test charge.

4. What is the significance of the direction of the electric field?

The direction of the electric field indicates the direction in which a positive test charge would move if placed in that field. It also determines the direction of the force that a charge would experience if placed in that field.

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

The electric field is inversely proportional to the square of the distance between the two point charges. This means that as the distance between the charges increases, the electric field decreases. As the distance decreases, the electric field increases.

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