Draw electric field lines of simple charge distribution.

A long cylindrical volume contains a uniformly distributed charge of density $\rho \;Cm ^{-3}$. The electric field inside the cylindrical volume at a distance $x =\frac{2 \varepsilon_{0}}{\rho} m$ from its axis is $…….Vm ^{-1}$

Given below are two statements:

Statement $I :$ An electric dipole is placed at the centre of a hollow sphere. The flux of electric field through the sphere is zero but the electric field is not zero anywhere in the sphere.

Statement $II :$ If $R$ is the radius of a solid metallic sphere and $Q$ be the total charge on it. The electric field at any point on the spherical surface of radius $r ( < R )$ is zero but the electric flux passing through this closed spherical surface of radius $r$ is not zero.

In the light of the above statements, choose the correct answer from the options given below:

Figure shows the electric field lines around three point charges $A, \,B$ and $C$.

$(a)$ Which charges are positive ?

$(b)$ Which charge has the largest magnitude ? Why ?

$(c)$ In which region or regions of the picture could the electric field be zero ? Justify your answer.

$(i)$ Near $A$          $(ii)$ Near $B$          $(iii)$ Near $C$    $(iv)$ Nowhere

The electric field components in Figure are $E_{x}=\alpha x^{1 / 2}, E_{y}=E_{z}=0,$ in which $\alpha=800 \;N / C\, m ^{1 / 2} .$ Calculate

$(a)$ the flux through the cube, and

$(b)$ the charge within the cube. Assume that $a=0.1 \;m$