(a(i))[2]
Fig. 6.2 shows how $V$ varies with the charge $Q$ on the plates of capacitor $C$ as the capacitor discharges. Show that the energy stored in capacitor $C$ at time $t = 0$ is $1.8\,\text{mJ}$.
(a(ii))[2]
Determine the capacitance of capacitor $C$. Include a unit in your answer.
(b(i))[2]
Fig. 6.3 shows how $-\ln\left(\dfrac{V}{8.0\,\text{V}}\right)$ changes with $t$. Show that, when $t$ is equal to one time constant, the value of $-\ln\left(\dfrac{V}{8.0\,\text{V}}\right)$ is $1.0$.
(b(ii))[1]
Determine the time constant $\tau$ for the circuit shown in Fig. 6.1.
(b(iii))[2]
Calculate the resistance of the resistor $R$.