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## Homework Statement

A +20nC point charge is placed on the x axis at x = 2.0 m, and a -25 nC point charge is placed on the y axis at y= -3.0 m. What is the angle that the direction of the electric field at the origin makes with the x-axis.

(a) 209 (deg)

(b) 61 (deg)

(c) 29 (deg)

(d) 241(deg)

(e) 119 (deg)

## Homework Equations

E = ke(q/r^2)

## The Attempt at a Solution

E= (8.99x10^9) [ (20x10^-9)/4 (i) - (25x10^-9)/9 (j)]

= (8.99x10^9) [ 5.0x10^-9 (i) - 2.78x10^-9 (j)]

= 44.95i - 24.97j

= 51.42

The angle between the x-axis is arccos(44.95/51.42) = 29 (deg)

But the correct answer is 209 (deg).