Exam 26: Charge Separation and Storage

A parallel-plate capacitor has a capacitance of 10 mF and is charged with a 20-V power supply.The power supply is then removed and a dielectric material of dielectric constant 4.0 is used to fill the space between the plates.What is the voltage now across the capacitor?

An ideal air-filled parallel-plate capacitor has round plates and carries a fixed amount of equal but opposite charge on its plates.All the geometric parameters of the capacitor (plate diameter and plate separation)are now DOUBLED.If the original capacitance was C₀,what is the new capacitance?

An ideal air-filled parallel-plate capacitor has round plates and carries a fixed amount of equal but opposite charge on its plates.All the geometric parameters of the capacitor (plate diameter and plate separation)are now DOUBLED.If the original energy stored in the capacitor was U₀,how much energy does it now store?

A parallel-plate capacitor,with air between the plates,is connected across a voltage source.This source establishes a potential difference between the plates by placing charge of magnitude 4.15 × 10^-6 _C on each plate.The space between the plates is then filled with a dielectric material,with a dielectric constant of 7.74.What must the magnitude of the charge on each capacitor plate now be,to produce the same potential difference between the plates as before?

A parallel-plate capacitor has a capacitance of 10 mF and charged with a 20-V power supply.The power supply is then removed and a dielectric material of dielectric constant 4.0 is used to fill the space between the plates.How much energy is now stored by the capacitor?

An ideal air-filled parallel-plate capacitor has round plates and carries a fixed amount of equal but opposite charge on its plates.All the geometric parameters of the capacitor (plate diameter and plate separation)are now DOUBLED.If the original energy density between the plates was u₀,what is the new energy density?

An air-filled capacitor is formed from two long conducting cylindrical shells that are coaxial and have radii of 48 mm and 84 mm.The electric potential of the inner conductor with respect to the outer conductor is -400 V.(k = 1/4πε₀ = 8.99 × 10⁹ N • m²/C²)The energy stored in a 1.0-m length of this capacitor is closest to

A metal cylinder of radius 2.0 mm is concentric with another metal cylinder of radius 5.0 mm.If the space between the cylinders is filled with air and the length of the cylinders is 50 cm,what is the capacitance of this arrangement? (k = 1/4πε₀ = 8.99 × 10⁹ N • m²/C²)

Two square air-filled parallel plates that are initially uncharged are separated by 1.2 mm,and each of them has an area of 190 mm².How much charge must be transferred from one plate to the other if 1.1 nJ of energy are to be stored in the plates? (ε₀₀ = 8.85 × 10^-12 C²/N • m²)

A parallel-plate capacitor has plates of area 0.40 m² and plate separation of 0.20 mm.The capacitor is connected across a 9.0-V potential source.(ε₀ = 8.85 × 10^-12 C²/N • m²) (a)What is the magnitude of the electric field between the plates? (b)What is the capacitance of the capacitor? (c)What is the magnitude of the charge on each plate of the capacitor?

A 1.0 m long piece of coaxial cable has a wire with a radius of 1.1 mm and a concentric conductor with inner radius 1.3 mm.The area between the cable and the conductor is filled with a dielectric.If the voltage drop across the capacitor is 6000 V when the line charge density is 8.8 μC/m,find the value of the dielectric constant.(k = 1/4πε₀ = 8.99 × 10⁹ N • m²/C²)

A 15-μF air-filled capacitor is connected to a 50-V voltage source and becomes fully charged. The voltage source is then removed and a slab of dielectric that completely fills the space between the plates is inserted. The dielectric has a dielectric constant of 5.0. (a)What is the capacitance of the capacitor after the slab has been inserted? (b)What is the potential difference across the plates of the capacitor after the slab has been inserted?

An ideal parallel-plate capacitor consists of a set of two parallel plates of area A separated by a very small distance d.When the capacitor plates carry charges +Q and -Q,the capacitor stores energy U₀.If the separation between the plates is doubled,how much electrical energy is stored in the capacitor?

An ideal parallel-plate capacitor consists of a set of two parallel plates of area A separated by a very small distance d.When this capacitor is connected to a battery that maintains a constant potential difference between the plates,the energy stored in the capacitor is U₀.If the separation between the plates is doubled,how much energy is stored in the capacitor?

Two thin-walled concentric conducting spheres of radii 5.0 cm and 10 cm have a potential difference of 100 V between them.(k = 1/4πε₀ = 8.99 × 10⁹ N • m²/C²) (a)What is the capacitance of this combination? (b)What is the charge carried by each sphere?

A parallel-plate capacitor with plate separation of 1.0 cm has square plates,each with an area of 6)0 × 10^-2 m².What is the capacitance of this capacitor if a dielectric material with a dielectric constant of 2.4 is placed between the plates,completely filling them? (ε₀ = 8.85 × 10^-12 C²/N • m²)

A 6.00-μF parallel-plate capacitor has charges of ±40.0 μC on its plates.How much potential energy is stored in this capacitor?

The capacitance per unit length of a very long coaxial cable,made of two concentric cylinders,is 50 pF/m.What is the radius of the outer cylinder if the radius of the inner one is 1.0 mm? (k = 1/4πε₀ = 8.99 × 10⁹ N • m²/C²)

An air-filled capacitor is formed from two long conducting cylindrical shells that are coaxial and have radii of 13 mm and 85 mm.The electric potential of the inner conductor with respect to the outer conductor is -600 V.(k = 1/4πε₀ = 8.99 × 10⁹ N • m²/C²)The maximum energy density of the capacitor is closest to

A 6.0-μF air-filled capacitor is connected across a 100-V voltage source. After the source fully charges the capacitor,the capacitor is immersed in transformer oil (of dielectric constant 4.5). How much ADDITIONAL charge flows from the voltage source,which remained connected during the process?