Energy stored by a capacitorAQA A-Level Physics: Mind map

Exam questions on Energy stored by a capacitor

1. A 2200 µF capacitor is charged from a 9.0 V battery until the p.d. across it is 9.0 V.
   Explain why a graph of charge against p.d. for this capacitor is a straight line through the origin, and show that the energy stored is ½QV.2 marks
2. A camera flash unit uses a 160 µF capacitor charged to 300 V. When the flash is fired, the capacitor discharges completely through the flash lamp in 2.0 ms.
   The unit is later charged to only 150 V. Calculate the energy now stored and state how it compares with the energy at 300 V.2 marks
3. A capacitor stores a charge of 3.0 mC when the p.d. across it is 12 V. A variable power supply is then used to change the p.d. across it.
   Calculate the capacitance of the capacitor and the energy stored at 12 V.3 marks