Only just started ac currents today and this was on my first quiz, I got 8/10 for it but got this question wrong. 1. The problem statement, all variables and given/known data A 100 ohm resistor is connected in series with a capacitor and a power supply, and the supply voltage is brought up to 200 mV. The graph shows- for three different capacitors- the decay of the voltage across the capacitor after the voltage source is "shorted out" . From the graph, estimate the capacitance in the circuit which gave the red decay curve. Calculate your answer in MICROFARADS, but do not include the units in your answer. 2. Relevant equations V=IR t=RC t=l/C 3. The attempt at a solution Really had no idea what to do on this question. V=IR --> R=V/I --> R=40/100 --> 0.4ohms c=t/R --> c=0.0001/0.4 --> 2.5E-4 --> 25MicroFarads. I know this is completely wrong but I got in trouble for not showing working last time. Any help would be appreciated.