\(\frac{1}{2} \mathrm{C}_{2} \mathrm{V}^{2}=4 \times \frac{1}{2} \mathrm{C}_{1} \mathrm{V}^{2}\)
\(\therefore \quad \mathrm{C}_{2}=4 \mathrm{C}_{1}\)
\(\therefore \quad \mathrm{C}_{1}=2 \;and\; \mathrm{C}_{2}=8\)
For series combination
\(C_{e q}=\frac{C_{1} C_{2}}{C_{1}+C_{2}}=1.6\)