Electric Field and Electric Potential

[orgo]

A charge of -10 microcoulumbs is located at the origin of an x-y coordinate system. Another charge of -10 microcoulumbs is located at the point (0, 2.0 m). Determine the electric field and the electric potential at the point (0, 1.0 m).

Here is what I did. Is this the correct way?

E1 = (9*10^9) (10*10^-6)/1^2 = 90,000 N/C
E2 = (9*10^9) (10*10^-6)/1^2 = 90,000 N/C
Etotal = 90,000 - 90,000 = 0 (Electric field)

V1 = (9*10^9) (-10*10^-6)/1^2 = -90,000 V
V2 = (9*10^9) (-10*10^-6)/1^2 = -90,000 V
Vtotal = -90,000 + -90,000 = -180,000 V (Electric potential)

 

[orgo]

help!

Please reply ASAP. I have an exam in about 10 hours!

 

[Gza]

It's correct. You should post at the k-12 board next time though.