Electric Circuits Answers

A 2.00 x10^(-9)F capacitor with an initial charge of 5.10 x 10^(-6) C is discharged through a 1.30Kilo ohm resistor.
(a) Calculate the current in the resistor 9.00s after the resistor is connected across the terminals of the capacitor.
(b) What charge remains on the capacitor after 8.00s? (c) What is the maximum current in the resistor?

A fixed capacitor of capacitance 10^(-4) microfarad is connected in series with a variable capacitor, the capacitance of which may be varied from zero to 10^(-4) microfarad in steps of 10^(-6) microfarad. These two in series are connected in parallel with a third capacitor of capacitance 5 x10^(-4) microfarad. Calculate:
(i) the maximum capacitance of the whole combination.
(ii) the smallest change in this capacitance which can be produced by the arrangement.

A 2.5 x 10^(-6)F capacitor is charged to a potential difference if 100V and is disconnected from the supply. Its terminals are then connected to those of an uncharged 10 x10^(-6)F capacitor. Find
(a) the resulting potential difference across the two capacitors and
(b) the total energy stored in them.
Compare the result in (b) with the energy originally stored in the 2.5 x 10^(-6)F capacitor and comment on the difference.

A capacitor of unknown capacitance has been charged to a potential difference of 100V and then disconnected from the battery. When the charged capacitor is then connected in parallel to an uncharged 10.0 mF capacitor, the pottential difference across the combination is 30.0 V. Calculate the unknown capacitance.

Capacitors C1 = 6.00 x 10^(-6)F and C2 = 2.00 x 10^(-6)F are charged as a parallel combination across a 250V battery. The capacitors are disconnected from the battery and from each other. They are then connected positive plate to negative plate and negative plate to positive plate. Calculate the resulting charge on each capacitor.

The voltage across in an air-filled parallel-plate capacitor is measured to be 85.0V.
When a dielectric is inserted and completely fills the space between the plates, the voltage drops to 25.0V
(i) What is the dielectric constant of the inserted material?

A 4.0 x 10^(-6) F capacitor is connected in series with a 3.0 x 10^(-6) F capacitor. This series combination is connected in parallek with a 6.0 x 10^(-6) F capacitor. The whole arrangement is then connected in series with a 12.0 V battery.
(i) Draw a curcuit diagram of the arrangement described above
(ii) Calculate the total charge in stored in the circuit and hence calculate the charge stored in each capacitor.

Two identical parallel-plate capacitirs, each with capacitance 10.0 x 10^(-6)F, are charged to potential difference 50.0V and then disconnected from the battery. They are then connected to each other in parallel with plates of like sign connected. Finally, the plate separation in one of the capacitors is doubled.
(i) Find the total energy of the system of two capacitors before the plate separation is doubled.
(ii) Find the potential difference across each capacitor after the plate separation is doubled.
(iii)Find the total energy of the system after the plate separation is doubled.

Two capacitors C1 =18.0 mF and C2 = 36.0 mF are connected in series and a 12.0V battery is connected across the two capacitors. Find
(i) the equivalent capacitance and the energy stored in this equivalent capacitance.
(ii) Find the energy stored in each individual capacitor

Two capacitors give an equivalent capacitance of 9.00 x10^(-6)F when connected in parallel and an equivalent capacitance of 2.00 x10^(-9) F when connected in series. What is the capacitance of each capacitor?