An uncharged metal sphere is placed between two charged plates as shown. The electric field lines look like:

If some charge is given to a solid metallic sphere,the field inside remains zero and by Gauss's law all the charge resides on the surface. Now,suppose that Coulomb's force between two charges varies as $1 / r^{3}$. Then,for a charged solid metallic sphere

The figure shows the electric field lines. The spacing between the lines is parallel to the paper at every point. If the magnitude of the field at $A$ is $40 \ N/C$,then the approximate magnitude of the field at $B$ is ....... $N/C$.

$A$ long straight wire of radius $1 \, mm$ has a uniform charge distribution. The charge per $cm$ length of the wire is $Q \, Coulombs$. $A$ cylinder of radius $50 \, cm$ and length $1 \, m$ encloses the wire symmetrically. The total flux passing through the surface of the cylinder is ..........

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 $\pi$)

In the figure,a $+Q$ charge is located at one of the corners of the cube. What is the electric flux through the cube due to the $+Q$ charge?