two capacitors of capacity 200 pF and 600 pF are connected in parallel and then charged to a potential of 120 V. Determine (a) the charge on each capacitor, (b) the total charge on each cpacitor and (c) the effective capacity of the combination.

Explanation

Here `C_1=200xx10^-12F,C_2=600xx10^-12F,V=120V`
(a) Charge on first capacitor,
`q_1 = C_1V=200xx10^-12xx120`
`=24xx10^-9C`
Charge on second capacitor,
`q_2 = C_2V= 600xx10^-12xx120`
`=72xx10^-9C`
(b) Total charge
`q=q_1+q_2`
`=(24xx10^-9)+(72xx10^-9)`
`=96xx10^-9C`
(c) Let the effective capacity be C. Capacitors are connected in parallel.
`C=C_1+C_2`
`=200xx10^-12+600xx10^-12`
`=800xx10^-12F`
`C=800muF = 800pF`
(a) `q_1=24xx10^-9C,q_2=72xx10^-9C`
(b) Total charge `q=96xx10^-9C`
(c) Effective capacitance C = 800pF