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 $C$.

$C_1$ and $C_2$ are two hollow concentric cubes enclosing charges $2Q$ and $3Q$ respectively as shown in the figure. The ratio of electric flux passing through $C_1$ and $C_2$ is:

$A$ solid uncharged conducting sphere has a radius of $3a$ and contains a hollowed spherical region of radius $2a$. $A$ point charge $+Q$ is placed at a position a distance $a$ from the common center of the spheres. What is the magnitude of the electric field at the position $r = 4a$ from the center of the spheres as marked in the figure by $P$? $\left( {k = \frac{1}{{4\pi { \in _0}}}} \right)$

An electric charge $q$ is placed at the centre of a cube of side $a$. The electric flux through one of its faces will be

The figure shows electric field lines due to a charge configuration. From this,we conclude that:

$A$ hollow cylinder has a charge $q$ coulomb within it. If $\phi$ is the electric flux in units of volt-meter associated with the curved surface $B$,the flux linked with the plane surface $A$ in units of volt-meter will be: