Question

What is the total electric flux through a closed surface containing a 2.0 μC charge?

Answer 1

The Gauss's law says

$$\phi=\oint EdA=\frac{q}{\epsilon_0}$$

$$\phi=\frac{2.0*10^{-6}}{8.85*10^{-12}}=2.3*10^5\:\rm N\cdot m^2/C$$