# Calculating the Electric FLux

Hello,

The problem:

A 3.60cm x 4.50cm rectangle lies in the xy-plane. What is the electric flux through the rectangle if E=(80.0i + 50k) N/C ?

My attempt:

First convert the rectangle units from cm to m.

4.50cm = 0.045m
3.60cm = 0.036m

Find the area of the rectangle.

A = 0.036m x 0.045m = 0.00162 m^2

Find the magnitude of the electric field.

E = sqrt (50^2 + 80^2) = 94.34 N?C (aprox.)

Multiply the two,

electric flux = E * A = 0.15283 Nm^2 / C (aprox.)

However, this answer is wrong. Could anyone point me in the right direction? Thank you.

BvU
Homework Helper
Hello arileah, This looks like homework and should be posted in the homework forum -- there's a mandatory template there.
Your error is at the point where you multiply the two: that is a vector multiplication, not a magnitude multiplication.

Hello arileah, This looks like homework and should be posted in the homework forum -- there's a mandatory template there.
Your error is at the point where you multiply the two: that is a vector multiplication, not a magnitude multiplication.

Thank you! I am new to using physics forums. I'll post it to the homework forum.