Capacitance and energy storedEdexcel International A Level Physics: Mind map

Exam questions on Capacitance and energy stored

1. A capacitor of capacitance 470 μF is connected across a 12 V d.c. supply until it is fully charged.
   The capacitor is now charged using a 6.0 V supply instead of 12 V. Calculate the energy stored and explain why it is not half of the energy stored at 12 V.2 marks
2. The flash unit of a camera contains a capacitor of capacitance 1500 μF. It is charged to a p.d. of 300 V and then discharged through the flash lamp in a pulse lasting 1.0 ms.
   Calculate the average power delivered to the flash lamp during the pulse.2 marks
3. A capacitor stores a charge of 2.4 mC when the potential difference across it is 8.0 V. The p.d. across a capacitor is directly proportional to the charge stored on it.
   Use a graph of potential difference against charge stored to derive an expression for the energy stored in the capacitor in terms of Q and V.3 marks