Resistors and Capacitors in Series and Parallel (4C) Practice Test

A biosensor readout circuit uses a capacitor network to set an integration window. Initially, a single capacitor $C = 20\ \text{nF}$ is used. The designer replaces it with two capacitors in series: $C_1 = 10\ \text{nF}$ and $C_2 = 10\ \text{nF}$. Which outcome would be expected for the equivalent capacitance of the network?

A system response test uses an RC low-pass stage where the resistor is formed by two series resistors ($R_1 = 10\ \text{k}\Omega$, $R_2 = 10\ \text{k}\Omega$) feeding a capacitor to ground ($C = 1\ \mu\text{F}$). Without changing $C$, the engineer shorts (bypasses) $R_2$ so only $R_1$ remains in series with the capacitor. Based on the configuration, which change is most likely to occur in the charging rate of the capacitor following a step input?