Statement$ -1$ : When a charge $q$ is take from the centre of the surface of the sphere its potential energy changes by $\frac{{q\rho }}{{3{\varepsilon _0}}}$
Statement$ -2$ : The electric field at a distance $r(r < R)$ from centre of the sphere is $\frac{{\rho r}}{{3{\varepsilon _0}}}$
$\frac{\rho r}{3 \epsilon_{0}}$
The electric potential inside a uniformly charged sphere
$=\frac{\rho R^{2}}{6 \epsilon_{0}}\left[3-\frac{r^{2}}{R^{2}}\right]$
$\therefore $ Potential difference between centre and surface
$=\frac{\rho R^{2}}{6 \epsilon_{0}}[3-2]=\frac{\rho R^{2}}{6 \epsilon_{0}}$
$\Delta \mathrm{U}=\frac{q \rho R^{2}}{6 \epsilon_{0}}$


$K(x) = K_0 + \lambda x$ ( $\lambda =$ constant)
The capacitance $C,$ of the capacitor, would be related to its vacuum capacitance $C_0$ for the relation

