Final answer:
The net flux through a cube in a uniform electric field, even when the electric field strength is doubled, is zero because the flux entering and exiting cancel each other out.
Step-by-step explanation:
The question is asking about the net flux through a cube in the presence of a uniform electric field when the electric field strength is doubled.
By definition, the electric flux (Φ) through a surface is the product of the electric field (E) and the area (A) it is penetrating, given by Φ = E ⋅ A ⋅ cos(θ), where θ is the angle between the field lines and the normal to the surface. For a cube with faces parallel to the coordinate planes, the electric field will be perpendicular to two opposite faces and parallel to the four remaining faces.
Since electric field lines enter through one face and exit through the opposite face, the net flux remains the same regardless of the electric field strength because the flux entering and exiting cancel each other out. Hence, even if the electric field strength is doubled, as long as it remains uniform and perpendicular to two opposite faces, the net flux through the cube remains zero.