
$\therefore \mathrm{W}_{\mathrm{CA}}=\mathrm{W}_{\mathrm{BA}^{-}}=-\int_{2 \mathrm{a}}^{\mathrm{a}} \frac{\lambda}{2 \pi \varepsilon_{0} \mathrm{r}} \mathrm{q} \mathrm{dr}=\frac{\mathrm{q} \lambda}{2 \pi \varepsilon_{0}} \operatorname{In} 2$
$\varepsilon(x)=\varepsilon_{0}+k x, \text { for }\left(0\,<\,x \leq \frac{d}{2}\right)$
$\varepsilon(x)=\varepsilon_{0}+k(d-x)$, for $\left(\frac{d}{2} \leq x \leq d\right)$
