Assume the two equal capacitors are 2 micro-farads respectively( you can assume any number) Effective capacitor in series = \(\frac{1}{C_1} + \frac{1}{C_2}\) = \(\frac{1}{2} + \frac{1}{2}\) = \(\frac{2}{2}\) = 1 micro-farads Effective capacitance in parallel = \(C_1 + C_2\) = 2 + 2 = 4 micro-farads The ratio of the effective series capacitance to the effective parallel capacitance = 1: 4 = \(\frac{1}{4}\) = 0.25