# Homework Help: Electric field of a point of charge

1. Sep 2, 2008

### ibaraku

1. The problem statement, all variables and given/known data
A point charge Q = 16.5uC is at the origin. Find the electric field vector at the point P with coordinates x = 15cm, y = 25cm, z = 0.

2. Relevant equations

E = kQ/d^2
F = QE

3. The attempt at a solution

Ok, so first to calculate the distance between the origin and point P I used the Pythagorean theorem, which comes out to be 29.15cm, or .2915m

Then I applied the formula above

[(9 x 10^9) (16 x 10^-6)] / [(.15)^2 + (.25)^2] which is equal to --->>> 1694117.647 N/C

so my question is
in order to get the electric field do I just multiply
(1694117.647) (16 x 10^-6) --->>> 27.11

it just doesn't seem right...
thanks

2. Sep 2, 2008

### granpa

why dont you break it down for us and tell us what all these numbers and equations mean.

3. Sep 2, 2008

### gendou2

1694117.647 N/C is the amplitude of the field vector at that point.
The direction of the vector is parallel to the hypotenuse.

4. Sep 2, 2008

### ibaraku

Ok I see, thanks