A 80uF capacitor is charged by a 50V battery.The capacitor is disconnected from the battery and then connected across another uncharged 320 uF capacitor. Calcuulate the charge on the second capacitor.
Q1 = charge on first capacitor = C1 V1 = 80u x 50 = 4000u C = 4mC
common potential after connecting them together
V = total charge / sum of capacitances
= (Q1 + Q2) / C1 + C2 = 4 x 10-3 / (80 + 320) x 10-6 = (4/400) x 103 = 1000/100 = 10 V
charge on second capacitor = C2 V = 320u x 10 = 3200u C = 3.2 m C