Flux - simple integral computation

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quantum13
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Homework Statement


A surface has the area vector A = 2i + 3j. What is the flux of a uniform electric field through it if the field is E = 4i?

2. Homework Equations
Integral calculus, vectors

The Attempt at a Solution


I don't understand why one could do this. The integral is of E and dA, not E and A. How can I use A to determine dA?

This is a crackpot way I thought of

[tex]\Phi = \int \vec{E} \cdot \vec{dA}[/tex]

[tex] \Phi = \vec{E} \cdot \int \vec{dA} [/tex]

[tex] \Phi = \vec{E} \cdot \vec{A} [/tex]

Then Phi = 4i dot (2i + 3j) = 8 flux units

This seems like wild fantasy though as I don't know if I can pull out a constant from a dot product integral
 
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