# Electric flux?

1. Feb 2, 2015

### cass

1. The problem statement, all variables and given/known data

The drawing shows an edge-on view of two planar surfaces that intersect and are mutually perpendicular. Surface (1) has an area of 2.20 m², while surface (2) has an area of 3.90 m². The electric field in the drawing is uniform and has a magnitude of 200 N/C. Find the magnitude of the electric flux through surface (2) if the angle θ made between the electric field with surface (2) is 35.0°.

2. Relevant equations

I used gausse law
3. The attempt at a solution

(200)(2.20)cos(35)=360.4
(200)(3.90)cos(35)=638.9
Sinnce they are looking for magnitude of surface 2 I thought the answer was 638.9 but I got it wrong.

2. Feb 2, 2015

### TSny

Welcome to PF!

You used cos(35) when calculating the flux through surface 2. Think about whether or not you used the correct angle here.

3. Feb 2, 2015

### cass

what do u mean?

4. Feb 2, 2015

### cass

ok since it is a 90 degree angle then subtracting 35 should give me 55 right?

5. Feb 2, 2015

### Brian T

Yes, using Gauss' Law, EAcosθ, where θ refers to the angle between the electric field's direction and the line perpendicular to the area of application (which is the dot product of E and A, E⋅A)

6. Feb 2, 2015

### cass

thank u!!!!!!!!!!