An electric field is given by $\vec{E} = (6 \hat{i} + 5 \hat{j} + 3 \hat{k}) \ N/C$. The electric flux through a surface area $\vec{A} = 30 \hat{i} \ m^2$ (in $SI$ units) is:

Four closed surfaces $S_1, S_2, S_3$ and $S_4$ together with charges $+q, -q$ and $-2q$ are shown. Through which one of the surfaces is the net flux zero?

When is electric flux said to be positive,negative,or zero?

$A$ charged body has an electric flux $\phi$ associated with it. The body is now placed inside a metallic container. The flux $\phi$ outside the container will be

$A$ 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 infinitely long wire has a uniform linear charge density $\lambda = 2 \ nC/m$. The net flux through a Gaussian cube of side length $a = \sqrt{3} \ cm$, if the wire passes through any two corners of the cube that are maximally displaced from each other, would be $x \ Nm^2 C^{-1}$, where $x$ is: [Neglect any edge effects and use $\frac{1}{4 \pi \varepsilon_0} = 9 \times 10^9 \ SI$ units] (in $\pi$)