# Uniform line of charge and point charge

## Homework Statement

An infinite line charge of uniform linear charge density lambda = -3.1 mu or micro CC/m lies parallel to the y axis at x = -1 m. A point charge of 0.7 mu or micro CC 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.

flux = E*A = Q/ε
E = kQ/r^2

## The Attempt at a Solution

X axis:
To find the electric field from the line only: gaussian cylinder, centered on the line and r = 4.5m.
E*2∏*4.5*L = λL/ε -> E1 = λ/(ε*9*∏) to the left

From the point:
E2 = K(.7*10^-6)/1.25*sin(63.43°) to the right

Ex = E2-E1 Right?

Y axis:
The line don't matter because it cancels itself out. right?
Ey = K(.7*10^-6)/1.25*cos(63.43°) Down

Both answers need to be in kN/C, I'm at a loss, do you guys have any ideas? I have tried many different answers and I've checked all of the units.

Last edited:

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TSny
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ehild
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ehild

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Welp, I just found my mistake. Damn Radians!