Answer:
Over a closed surface
Explanation:
Gauss's law: It states that the total electric flux passing through the closed surface is equal to [tex]\frac{1}{\epsilon_0}[/tex] times the total charge enclosed within the surface.
Mathematically representation :
Electric flux=[tex]\phi=\oint E\cdot dA=\frac{q}{\epsilon_0}[/tex]
Where q=Total charge enclosed within surface
[tex]\epsilon=8.85\times 10^{-12}C^2/Nm^2[/tex]=Permittivity of vacuum
Therefore,the integral in Gauss's law should be evaluated over a closed surface.
Circle in the integration mean closed we can say that closed integral.
