Exam 25: Capacitance

A parallel-plate capacitor, with air dielectric, is charged by a battery, after which the battery is disconnected. A slab of glass dielectric is then slowly inserted between the plates. As it is being inserted:

A 20-F capacitor is charged to 200 V. Its stored energy is:

A battery is used to charge a parallel-plate capacitor, after which it is disconnected. Then the plates are pulled apart to twice their original separation. This process will double the:

Two conducting spheres have radii of R₁ and R₂ with R₁ greater than R₂. If they are far apart the capacitance is proportional to:

A capacitor C "has a charge Q". The actual charges on its plates are:

Two identical capacitors, each with capacitance C, are connected in parallel and the combination is connected in series to a third identical capacitor. The equivalent capacitance of this arrangement is:

Let Q denote charge, V denote potential difference and U denote stored energy. Of these quantities, capacitors in series must have the same:

A 2- $\mu$ F and a 1- $\mu$ F capacitor are connected in series and charged from a battery. They store charges P and Q, respectively. When disconnected and charged separately using the same battery, they have charges R and S, respectively. Then:

Let Q denote charge, V denote potential difference and U denote stored energy. Of these quantities, capacitors in parallel must have the same:

Two parallel-plate capacitors with the same plate separation but different capacitance are connected in parallel to a battery. Both capacitors are filled with air. The quantity that is NOT the same for both capacitors when they are fully charged is:

A charged capacitor stores 10 C at 40 V. Its stored energy is:

The diagram shows six 6- $\mu$ F capacitors. The capacitance between points a and b is:

Each of the four capacitors shown is 500 $\mu$ F. The voltmeter reads 1000V. The magnitude of the charge, in coulombs, on each capacitor plate is:

The capacitance of a parallel-plate capacitor can be increased by:

A dielectric slab is slowly inserted between the plates of a parallel plate capacitor, while the potential difference between the plates is held constant by a battery. As it is being inserted:

The plate areas and plate separations of five parallel plate capacitors are Rank these according to their capacitances, least to greatest.

A battery is used to charge a series combination of two identical capacitors. If the potential difference across the battery terminals is V and total charge Q flows through the battery during the charging process then the charge on the positive plate of each capacitor and the potential difference across each capacitor are:

If the plate area of an isolated charged parallel-plate capacitor is doubled:

An air-filled parallel-plate capacitor has a capacitance of 1 pF. The plate separation is then doubled and a wax dielectric is inserted, completely filling the space between the plates. As a result, the capacitance becomes 2 pF. The dielectric constant of the wax is:

A 2- $\mu$ F and a 1- $\mu$ F capacitor are connected in series and charged by a battery. They store energies P and Q, respectively. When disconnected and charged separately using the same battery, they have energies R and S, respectively. Then: