Charge $=600 \mathrm{V}$
Parallel capacitor $=1.0 \mu F$ $0.2 \times 600=\frac{V}{0.1}$
or, $V=0.2 \times 0.1 \times 600$
$\quad=\frac{2}{10} \times \frac{1}{10} \times 600$
$2 \times \frac{600}{12}=50 \times 2=100 \mathrm{V}$

Reason : The field just outside the capacitor is $\frac{\sigma }{{{\varepsilon _0}}}$. ( $\sigma $ is the charge density).


