State two roles that capacitors play in electrical circuits.
In Fig. 5.1, three capacitors each marked $30\,\mu\text{F}$ and $6\,\text{V max}$ are connected as shown. Find the total capacitance of the arrangement in Fig. 5.1.
Determine the largest potential difference that may be safely applied between points A and B.
In Fig. 5.1, three capacitors each labelled $30\,\mu\text{F}$ and $6\,\text{V max}$ are connected as shown. For this arrangement, determine (i) the total capacitance, and (ii) the maximum potential difference that can safely be applied between points A and B.
A capacitor with capacitance $4700\,\mu\text{F}$ is charged to a potential difference of $18\,\text{V}$. It is then partly discharged through a resistor, until the potential difference falls to $12\,\text{V}$. Calculate the energy dissipated in the resistor during the discharge.