An electronic flash unit in a camera uses a 22 μF22\ \mu\text{F}22 μF capacitor charged by a 15 V battery. The initial charge on the capacitor is Q0Q_0Q0. When the shutter is released, the capacitor discharges through a 150 kΩ150\text{ k}\Omega150 kΩ resistor. The time constant of this discharge circuit is TTT.
Which statement is correct?
The time constant TTT of the discharging circuit is 3.3 ms3.3\text{ ms}3.3 ms.
After a time TTT, the potential difference across the capacitor is 5.5 V5.5\text{ V}5.5 V.
The initial charge Q0Q_0Q0 on the capacitor is 33 μC33\ \mu\text{C}33 μC.
After a time 2T2T2T, the charge on the capacitor is Q0e2Q_0 e^{2}Q0e2.
63 exam-style questions on AQA A Level Physics Capacitance (A-level only), covering Capacitance (A-level only), Parallel plate capacitor (A-level only), Energy stored by a capacitor (A-level only), and Capacitor charge and discharge (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.