Draw the electric field lines for a negative point charge.

$A$ point charge is distributed in a small volume. The electric flux through a spherical surface of radius $10 \ cm$ enclosing the charge is $20 \ Vm$. What is the electric flux through a concentric spherical surface of radius $20 \ cm$?

$A$ hollow cylinder has a charge $q$ inside it. If $\phi$ is the electric flux in units of $\text{V}\cdot\text{m}$ associated with the curved surface $B$, what is the flux linked with the plane surface $A$ in units of $\text{V}\cdot\text{m}$?

Two point charges $2q$ and $q$ are placed at vertex $A$ and the centre of face $CDEF$ of the cube, respectively, as shown in the figure. The electric flux passing through the cube is:

If a charge $q$ is placed at the centre of the flat surface of a closed hemispherical non-conducting surface,what is the total electric flux passing through the flat surface?

$A$ charged particle $q$ is placed at the centre $O$ of a cube of side length $L$ $(A, B, C, D, E, F, G, H)$. Another identical charge $q$ is placed at a distance $L$ from $O$, outside the cube, as shown in the figure. The electric flux through the face $BGFC$ is