Within a spherical charge distribution of charge density ρ(r), N equipotential surfaces of potential V_0, V_0+Δ V, V_0+2 Δ V, … … …. V_0+ N Δ V (Δ V…

Within a spherical charge distribution of charge density $\displaystyle \rho(r), N$ equipotential surfaces of potential $\displaystyle \mathrm{V}_0, \mathrm{~V}_0+\Delta \mathrm{V}, \mathrm{V}_0+2 \Delta \mathrm{~V}$, $\displaystyle \ldots \ldots \ldots . \mathrm{V}_0+\mathrm{N} \Delta \mathrm{V}(\Delta \mathrm{V}>0)$, are drawn and have increasing radii $\displaystyle r_0, r_1, r_2, \ldots \ldots \ldots . r_N$, respectively. If the difference in the radii of the surfaces is constant for all values of $\displaystyle \mathrm{V}_0$ and $\displaystyle \Delta \mathrm{V}$ then :