$q_1, q_2, q_3$ and $q_4$ are point charges located as shown in the figure,and $S$ is a spherical Gaussian surface of radius $R$. Which of the following is true according to Gauss's law?

$A$ hollow cylinder has a charge '$q$' $C$ within it. If '$\phi$' is the electric flux associated with the curved surface $B$,the flux linked with the plane surface $A$ will be

$A$ charge of $1 \,C$ is located at the centre of a sphere of radius $10 \,cm$ and a cube of side $20 \,cm$. The ratio of outgoing flux from the sphere and cube will be

$A$ cubical region of side $a$ has its centre at the origin. It encloses three fixed point charges,$-q$ at $(0, -a/4, 0)$,$+3q$ at $(0, 0, 0)$,and $-q$ at $(0, +a/4, 0)$. Choose the correct option$(s)$.
$(A)$ The net electric flux crossing the plane $x = +a/2$ is equal to the net electric flux crossing the plane $x = -a/2$.
$(B)$ The net electric flux crossing the plane $y = +a/2$ is more than the net electric flux crossing the plane $y = -a/2$.
$(C)$ The net electric flux crossing the entire region is $\frac{q}{\varepsilon_0}$.
$(D)$ The net electric flux crossing the plane $z = +a/2$ is equal to the net electric flux crossing the plane $x = +a/2$.

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

$A$ linear charge having linear charge density $\lambda$ penetrates a cube diagonally and then it penetrates a sphere diametrically as shown. What will be the ratio of flux coming out of the cube and the sphere?