If K is the dielectric constant of the medium r₁ and r₂ the inner and outer radius of sphere respectively, then capacity of spherical condenser is given by

In M.K. S. system, the capacity of e spherical condenser is given by $\mathrm{C}=\mathrm{K}\cdot \left(4{\mathrm{\pi \epsilon }}_0\right)\left[{\mathrm{r}}_1{\mathrm{I}}_2/\left({\mathrm{r}}_2-{\mathrm{r}}_1\right)\right]$
In C.G.S. system ${\mathrm{C}}^{\mathrm{\prime }}=\left(\mathrm{C}/4{\mathrm{\pi \epsilon }}_0\right)$
$\therefore {\mathrm{C}}^{\mathrm{\prime }}=\frac{\mathrm{K}\left(4{\mathrm{\pi \epsilon }}_0\right)}{\left(4{\mathrm{\pi \epsilon }}_0\right)}\left[\frac{{\mathrm{r}}_1{\mathrm{r}}_2}{\left({\mathrm{r}}_2-{\mathrm{r}}_1\right)}\right]$
or     ${\mathrm{C}}^{\mathrm{\prime }}=\mathrm{K}\left[\frac{{\mathrm{r}}_1{\mathrm{r}}_2}{\left({\mathrm{r}}_2-{\mathrm{r}}_1\right)}\right]$