AP PHYSICS

posted by .

A 3.0-uF capacitor and a 4.0-uF capacitor are connected in series across a 40.0-V battery. A 10.0-uF capacitor is also connected directly across the battery terminals. Find the total charge that the battery delivers to the capacitors.

I NEED HELP WITH THIS PROBLEM. THANKS!

• AP PHYSICS -

If I understand the circuit, the 3.0 and 4.0 uF capacitors are connected in series with a 10.0 uF capacitor connected in parallel and all of this across a 40 v cell. First determine the capacitance of the series 3.0 and 4.0.
1/C = 1/3.0 + 1/4.0 = 1.7 uF.
Then add in the parallel 10.0 to make a total of 11.7 uF.
Q = Coulombs of stored electricity = CV where C is capacitance (in F) and V is voltage. Check my thinking.

• AP PHYSICS -

For the 10 uF capacitor,
Q' = C' V = (10*10^-6)*40 = 400 uC
For the series 4 uF and 3 uF capacitors, which both acquire the same charge Q",
10 V = Q"/4*10^-6 + Q"/3*10^-6
= Q"/1.714*10^-6
The two series capacitors act like a single 1.714 uF capacitor
Q" = 17.14 uC is the charge on both the 3 uF and 4 uF capacitors

• AP PHYSICS (correction) -

I forgot to use 40 V for the series capacitors. Their charge is 4 times higher than what I stated. Also, the battery only has to deliver a charge of Q", not the sum of the charges on the two series capacitors, which would be 2Q"

DrBob222 already provided a correct answer by computing an effective C for all three capacitors in series-parallel

Similar Questions

1. Physics

A 3.00 uF and a 5.00 uF capacitor are connected in series cross a 30.0V battery. A 7.00 uF capacitor is then connected in parallel across the 3.00 uF capacitor. a)Calculate the equivalent capacitance of the circuit I think the answer …
2. physics

Having trouble with this one: A capacitor having a capacitance of 10uF is charged by 100v battery. A.)Calculate the charge on the capacitor?
3. Physics

A)Two identical resistors are connected in parallel across a 30-V battery, which supplies them with a total power of 7.0 W. While the battery is still connected, one of the resistors is heated so that its resistance doubles. The resistance …
4. Physics

A)Two identical resistors are connected in parallel across a 30-V battery, which supplies them with a total power of 7.0 W. While the battery is still connected, one of the resistors is heated so that its resistance doubles. The resistance …
5. Physics

A parallel plate capacitor with plate separation d is connected to a battery. The capacitor is fully charged to Q Coulombs and a voltage of V. (C is the capacitance and U is the stored energy.) Answer the following questions regarding …
6. Physics

A 4.19-F and a 7.46-F capacitor are connected in series across a 35.0-V battery. A 8.46-F capacitor is then connected in parallel across the 4.19-F capacitor. Determine the voltage across the 8.46-F capacitor.
7. Physics

Three parallel plate capacitors (C1,C2 and C3 ) are in series with a battery of 100 V. C1=2500 micro Farad; C2=2C1 , C3=3C1 . (a) What is the potential difference over each capacitor and how much charge is on each capacitor?
8. PHYSICS

Two capacitors C1 = 7.00 µF and C2 = 11.0 µF are connected in series to a 9.00 V battery. (a) Find the equivalent capacitance of the combination. µF (b) Find the potential difference across each capacitor. (c) Find the charge on …
9. Physics

A 11.0-µF capacitor and a 50.0-µF capacitor are charged by being connected across separate 55.0-V batteries. (a) Determine the resulting charge on each capacitor. (b) The capacitors are then disconnected from their batteries and …
10. physics

Three capacitors are connected to a battery of unknown voltage as shown in the circuit diagram above. The voltage drop across capacitor C 1 is V 1 = 11 . volts. a) What is the effective capacitance of the three capacitors?

More Similar Questions