Given:

Total charge inside the cube, q = 2.0 μC

Edge length of Cube, a = 9.0 cm

We know that,

Flux, Φ = q/ε₀

Where, q = net charged enclosed

ε₀ = permittivity of free space

ε₀ = 8.85 × 10^-12N^-1 m^-2C²

⇒ Φ = 2.26 × 10⁵ Nm²C^-1

The net electric flux through the cubic Gaussian surface is Φ = 2.26 × 10⁵ Nm²C^-1

NOTE: The flux through a Gaussian surface depends on the net charge enclosed by it. Geometry has no effect on the total flux.