# Electric field of an infinite line charge and a point charge

1. Sep 29, 2010

### amilkovi

Electric field of an infinite line charge and a point charge!!!

1. The problem statement, all variables and given/known data
An infinite line charge with linear charge density $$\lambda$$=2.0$$\mu$$C/m lies along the y-axis. A point charge of 8.0 $$\mu$$C is locate at (x,y)=(-1.0m, 2.0m). Find (a) the electric field at (x,y)=(1.0m, 2.0m) (b) Find the force on a charge of -2.0$$\mu$$C placed at (x,y)=(1.0m, 2.0m).

I would love if someone could point me into the right direction here!
2. Relevant equations

3. The attempt at a solution
I believe I'm gona have to add the electric field of both the line and the point charge at the point (1.0m, 2.0m) for part (a)? Then for part (b) do the same except apply the negative charge at the same point and subtract its electric field?
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Sep 30, 2010

### vela

Staff Emeritus
Re: Electric field of an infinite line charge and a point charge!!!

Yes.
No. The negative charge feels a force due to the fields of the other charges. You don't need to take into account the field due to itself.