Physics - Electrostatics Question with Solution | TestHub

Two co-axial conducting cylinders of same length $\ell$ with radii $\sqrt{2}\mathrm{R}$ and $2R$ are kept, as shown in Fig. 1. The charge on the inner cylinder is $Q$ and the outer cylinder is grounded. The annular region between the cylinders is filled with a material of dielectric constant $\kappa =4$. Consider an imaginary plane of the same length $\ell$ at a distance R from the common axis of the cylinders. This plane is parallel to the axis of the cylinders. The cross-sectional view of this arrangement is shown in Fig.2. Ignoring edge effects, the flux of the electric field through the plane is :- ( ${\in }_0$ is the permittivity of free space)