Final answer:
The electric flux through a square in the r-y plane with a uniform electric field E = (2.0i + 3.0j) N/C is zero because the electric field is perpendicular to the normal of the plane of the square.
Step-by-step explanation:
You have asked to find the electric flux through a square in the r-y plane with an area of 4.0 cm2 in a uniform electric field E = (2.0i + 3.0j) N/C. Electric flux (Ψ) is given by the formula Ψ = E ⋅ A ⋅ cos(θ), where E is the electric field, A is the area through which the field is passing, and θ is the angle between the field and the normal to the surface.
In your case, since the square lies in the r-y plane, we can infer that the normal to the surface is along the z-axis. Therefore, the electric field component along the z-axis is not relevant, as the electric field and the normal to the square are perpendicular (90° apart). Hence, the electric flux through the square is zero, as cos(90°) = 0.