An electric line of force in the $xy$ plane is given by equation ${x^2} + {y^2} = 1$. A particle with unit positive charge, initially at rest at the point $x = 1,\;y = 0$ in the $xy$ plane

An infinite, uniformly charged sheet with surface charge density $\sigma$ cuts through a spherical Gaussian surface of radius $R$ at a distance $x$ from its center, as shown in the figure. The electric flux $\Phi $ through the Gaussian surface is

A cone of base radius $R$ and height $h$ is located in a uniform electric field $\vec E$ parallel to its base. The electric flux entering the cone is

A sphere of radius $R$ and charge $Q$ is placed inside a concentric imaginary sphere of radius $2R$. The flux associated with the imaginary sphere is

A circular disc of radius $R$ carries surface charge density $\sigma(r)=\sigma_0\left(1-\frac{r}{R}\right)$, where $\sigma_0$ is a constant and $r$ is the distance from the center of the disc. Electric flux through a large spherical surface that encloses the charged disc completely is $\phi_0$. Electric flux through another spherical surface of radius $\frac{R}{4}$ and concentric with the disc is $\phi$. Then the ratio $\frac{\phi_0}{\phi}$ is. . . . . .

Draw electric field lines when two positive charges are near.