Exam 26: Capacitors and Dielectrics

A solid spherical dielectric having $K = 3.1$ and radius of 6.2 cm has -3.5 nC of charge uniformly distributed throughout the sphere. The magnitude of the electric field at the surface is

A parallel-plate capacitor has (one) plate area of 7.6 cm $2$ and a separation distance between the two plates of 0.55 mm. There is a nylon dielectric, $k = 3.5$ , between the plates. The potential across the plates is 12 V. The electric field between the plates is

A 1300-N/C electric field in a polyethylene dielectric, $K = 2.3$ , has an energy density of

Consider capacitors $c _ { 1 } = 1 \mathrm {~F} , c _ { 2 } = 4 \mathrm {~F} , c _ { 3 } = 9 \mathrm {~F} , c _ { 4 } = 16 \mathrm {~F} , \ldots , c _ { n } = n ^ { 2 } \mathrm {~F}$ , with $n \rightarrow \infty$ . If these infinite number of capacitors are connected in parallel, the effective capacitance as seen by the source is

We can calculate the electric potential energy of a system by considering the contributions from

Consider the potential across the plates of a parallel-plate capacitor. As the potential is increased, the following occur:

The capacitance of a metal sphere of radius R is given by

A 5.5- $\mu$ F capacitor has 1.3 mJ of potential energy stored in it. The potential across the plates is

The energy density associated with an electric field is proportional to

An unknown capacitor has a potential of 18 V across the plates; the amount of charge on one of the plates is 4.7 mC. The potential energy stored in the capacitor is

A parallel-plate capacitor has (one) plate area of 26 cm $2$ and a separation distance between the two plates of 1.1 mm. The potential across the plates is 12 V. The electric field between the plates is

A parallel-plate capacitor has capacitance of $6.5 \times 10 ^ { - 8 }$ F and charge of $8.1 \times 10 ^ { - 11 }$ C. The potential across the plates is

The capacitance of a solid metal sphere having a radius of 20 cm is

The capacitance of a metal parallel-plate capacitor is a function of

Three capacitors, A, B, and C, are connected in series to a source. The effective capacitance as seen by the source is

A parallel-plate capacitor, having a vacuum dielectric, has capacitance of 620 $\mu$ F. A Plexiglas dielectric, $k = 3.4$ , is inserted between the plates. The new capacitance is

Three capacitors, A, B, and C, are connected in parallel to a source. The effective capacitance as seen by the source is

A 7.5 $\mu$ F parallel-plate capacitor having a plate separation distance of 0.25 mm has 8.2 mC of charge (magnitude per plate). The electric field between the plates is

We can effectively increase the capacitance of a charged parallel-plate capacitor by decreasing the separation distance between the plates until

Three equal capacitors, each of capacitance A, are connected in series. The effective capacitance (as seen by the source)