$A$ point source of $3000 \ lumen$ is located at the centre of a cube of side length $2 \ m$. The flux through one side is......$lumen$.

Consider the charges and the Gaussian surface shown in the figure. When calculating the electric flux through the spherical surface,the electric field is due to which of the following?

How do electric field lines depend on the area or the solid angle subtended by the area?

$A$ point charge causes an electric flux of $-2 \times 10^4 \ Nm^2 C^{-1}$ to pass through a spherical Gaussian surface of $8.0 \ cm$ radius,centred on the charge. The value of the point charge is: (Given $\epsilon_0 = 8.85 \times 10^{-12} \ C^2 N^{-1} m^{-2}$)

Two equations are given below:
$A. \oint E \cdot dA = \frac{Q}{\varepsilon_0}$
$B. \oint B \cdot dA = 0$
They are:

Draw the electric field lines for a system of two identical positive charges placed near each other.