Electric field from a charge q1

[happyparticle]

Homework Statement

Electric fields vector

Relevant Equations

Electric fields vector

Hi,
I have a charge q1 = -10 * 10^9. The the coordinatesare (3,4)m.
I found the electric field vector that is (-2160i -2880j) n/c.

My questions is if I add a charge q2 to the the coordinates(0,0) is the electric field stay the same?

 

[PeroK]

Homework Statement:: Electric fields vector
Relevant Equations:: Electric fields vector

Hi,
I have a charge q1 = -10 * 10^9. The the coordinatesare (3,4)m.
I found the electric field vector that is (-2160i -2880j) n/c.

My questions is if I add a charge q2 to the the coordinates(0,0) is the electric field stay the same?

Do you mean the electric field at the origin?

 

[happyparticle]

Actually, I'm not sure. I had to find the electric field without the charge q2 and then I have a second question that ask what happen to the field calculated if we add a charge q2 at the origin.

 

[PeroK]

Actually, I'm not sure. I had to find the electric field without the charge q2 and then I have a second question that ask what happen to the field calculated if we add a charge q2 at the origin.

Where is the charge $q_1$ and where are you calculating the electric field?

 

[happyparticle]

q1 is at the point (3m,4m) I calculated the electric field at the origin, but without the charge q2.

 

[PeroK]

q1 is to the point (3m,4m) I calculated the electric field at the origin, but without the charge q2.

The electric field at a point excludes any charge at that point. If you tried to apply the formula for the electric field of a point charge at the point itself, then you have undefined division by zero.

If you consider the point charge as an infinitesimal symmetric distribution of charge, then the field at the centre would be zero. That's how you should treat the situation here.

 

[happyparticle]

I'm not sure to understand.
I used E = k(q/r²) to find the electric field from (3m,4m) to the origin by the charge q1.

Is that correct?

 

[PeroK]

I'm not sure to understand.
I used E = k(q/r²) to find the electric field from (3m,4m) to the origin by the charge q1.

Is that correct?

Yes. What would the field be at the point $(3m, 4m)$?

The answer is that it has to be zero, as a point charge cannot exert a net force on itself.

 

[happyparticle]

If I have a charge q2 at the origin the electric field by q1 is the same?

 

[PeroK]

If I have a charge q2 at the origin the electric field by q1 is the same?

I'm not sure I understand that. The electric field at the origin does not change if you put a charge at the origin.

 

[happyparticle]

Alright! That was my question sorry. I wasn't sure about that. Thanks!