Answer to Question #287198 in Electricity and Magnetism for Angel

Question

A soccer goal, found in a city park, is made of tubing that supports an

odd-shade hanging net behind the goal, but has a rectangular opening

in front. The height of the opening is 2.8m and the width is 3.5m.

If a uniform electric field, with magnitude of 0.1N/C, passes through

the goal from the front to the back, entering at 90 degrees to the plane

of the goal opening, what is the flux through the net? Also, find the flux

through the net if the electric field enters the goal at 60 degrees angle

to the plane of the front of the goal. In both cases, assume that there is

no charge found inside the goal itself.

Answer 1

The flux at 90° is

$$\Phi=EA=Eab=0.98\text{ N}·\text m^2/\text C.$$

At 60°:

$$\Phi=EA\sin60°=Eab\sin60°=0.85\text{ N}·\text m^2/\text C.$$