If the number of electric lines of force emerging out of a closed surface is $1000$ , then the charge enclosed by the surface is .......... $C$

As shown in figure, a cuboid lies in a region with electric field $E=2 x^2 \hat{i}-4 y \hat{j}+6 \hat{k} \quad N / C$. The magnitude of charge within the cuboid is $n \varepsilon_0 C$. The value of $n$ is $............$ (if dimension of cuboid is $1 \times 2 \times 3 \;m ^3$ )

An electric field is given by $(6 \hat{i}+5 \hat{j}+3 \hat{k}) \ N / C$.

The electric flux through a surface area $30 \hat{\mathrm{i}}\; m^2$ lying in $YZ-$plane (in SI unit) is

Why do electric field lines not form closed loop ?

Electric charge is uniformly distributed along a long straight wire of radius $1\, mm$. The charge per $cm$ length of the wire is $Q$ $coulomb$. Another cylindrical surface of radius $50$ $cm$ and length $1\,m$ symmetrically encloses the wire as shown in the figure. The total electric flux passing through the cylindrical surface is

A cube is placed inside an electric field, $\overrightarrow{{E}}=150\, {y}^{2}\, \hat{{j}}$. The side of the cube is $0.5 \,{m}$ and is placed in the field as shown in the given figure. The charge inside the cube is $.....\times 10^{-11} {C}$