# physics E&M

posted by
**aaron b. (again sorry)**
.

I posted a question on here earlier but I wasn't able to solve from what the person had told me.

An infinite line charge of uniform linear charge density lambda = -2.5 micro Coulombs lies parallel to the y axis at x = 0 m. A point charge of 3.5 micro Coulombs is located at x = 2.5 m, y = 3.5 m. Find the x- and y-components of the electric field at x = 3.5 m, y = 3.0 m.

I was given a couple link to how to deal with things but I have some questions.

The line infinite line charge equation I saw gave the formula Ez=lambda/(2*pi*epslion naught*z) or with an r in place of z; but since my charge is parallel to the y-axis and

x=0 its at the origin (I think) and so I'm unsure of what distance I need. It seems like the line charge has neither an x or y charge.

Is it the distance to the point charge? If its the distance to the axes then I'm dividing by zero either way.

Also, as for direction, its positive to negative right? So the direction for adding vectorially is from the point charge to the line charge (to the left)?

Please help and thank you again.