Question

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.

So I get what this is asking; you have to point charges with locations given; what is the charge of the third at another given location. What I'm *not* sure of is what equations/approach to use.

I don't want to throw anyone under the bus (knowledge of the material is my responsibility) but my prof. just kinda mumbles and points at PowerPoint slides with a laser pointer so I don't have anything from my lecture to help with this. Any assistance would be much obliged; thank you in advance.

Answer 1

You have the electric field at (3.5,3) due to a line charge.
Then you have the electric field at (3.5,3) due to a point charge

You add those vectorialy to get the total E vector at (3.5,3)
Do that by adding the Ey components due to each
and then the Ey components due to each.
It only asks for those components, not the magnitude and direction.

The E field due to a line charge is in your text.
The E field due to a point charge is in your text.
I will see if I can find something online, but I am sure you have those.

Answer 2

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elelin.html

Answer 3

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elefie.html

Answer 4

in both cases we are talking about Coulomb's law E = k Q/r^2

Above I mean find Ex and Ey, not Ey and Ey (typo)

Answer 5

by the way k = 9*10^9 N m^2/C^2