What will be the total flux through the faces of the cube as shown in the figure with side of length $a$ if a charge $q$ is placed at:
$(a)$ $C$: centre of a face of the cube.
$(b)$ $D$: midpoint of $B$ and $C$.

(N/A) If the charge $q$ is placed at $C$,the centre of a face of the cube,the flux is shared equally by $2$ adjacent cubes.
Therefore,the flux through each cube is:
$\phi = \frac{q}{2\epsilon_{0}}$
$(b)$ If the charge $q$ is placed at $D$,the midpoint of the edge $BC$,the charge is shared by $4$ adjacent cubes.
Therefore,the flux through each cube is:
$\phi = \frac{q}{4\epsilon_{0}}$