( 2 marks ) c The switch S is now opened i State the initial reading of ammeters A 1 and A 2 . ( 1 mark ) ii Calculate the value of the time constant for the decay of charge on the capacitor. ( 1 mark ) iii Plot a graph on the axes of Figure 11to show the reading of ammeter A 2 from t 0, when the switch S is opened, to t 1.5 s. Label the y -axis with a suitable scale. Figure 11 ( 3 marks ) OCR Physics A, June 2009 6 a A 2.0 F capacitor is charged through a resistor from a battery of e.m.f. 6.0 V. i Sketch a graph on the axes of Figure 12 to show how the charge stored, Q , varies with the potential difference, V , across the capacitor during the charging process. Mark appropriate values on the axes of the graph.
21 Capacitance Exam-style questions OCR Physics A © Oxford University Press 2016 This resource sheet may have been changed from the original 9 Figure 12 ( 2 marks ) ii Calculate the energy stored by the capacitor when the potential difference across it is 2.5 V. ( 2 marks ) b Two circuits are set up as shown in Figure 13. The boxes A and B conceal an arrangement of two identical capacitors. The circuits are identical in every way apart from the boxes A and B . Figure 13