A capacitor has a disk-shaped dielectric of ceramic (εr = 7500) that has a 0.78 cm diameter and 0.928 mm thick. The disk insulator is parallel-coated on both sides with silver, these coating being plates. Find the capacitance, in nF, of the material.

A 31 m length of coaxial cable has a solid cylindrical wire inner conductor with a di- ameter of 2.168 mm and carries a charge of 10.02 µC. The surrounding conductor is a cylindrical shell and has an inner diameter of 11.534 mm and a charge of-10.02 C. What is the capacitance of this cable? As- sume the region between the conductors is air. The value of the Coulomb comstant is 8.98755 x 10° N m²/C. Answer in units of nF.

In Lab 3, we measured the dielectric constant of glass using a parallel plate capacitor. Suppose that a piece of flat glass panel with a linear dielectric constant ɛ, = 2.5 is inserted between the plates of such a capacitor. The thickness of the glass is d = 5mm. The glass is in contact with both plates. One of the plates of the capacitor is kept at +3V, and the other plate is grounded. Treat the plates as infinitely large and thus the electric field is uniform between the plates. a) Calculate the electric field between the plates. b) Calculate the (uniform) polarization created in the glass. c) Calculate the surface bound charge density on the side of the glass that is in contact with the positive plate of the capacitor. d) Calculate the electric displacement between the plates. e) Calculate the free charge per unit area on the positive plate of the capacitor.

A cylindrical capacitor consists of a solid inner conducting core with radius 0.270 cm, surrounded by an outer hollow conducting tube. The two conductors are separated by air, and the length of the cylinder is 13.0 cm. The capacitance is 39.0 pF. Part A: Calculate the inner radius of the hollow tube. r=__cm Part B: When the capacitor is charged to 135 V, what is the charge per unit length λ on the capacitor? λ=__C/m

A Geiger-Mueller tube is a radiation detector that consists of a closed, hollow, metal cylinder (the cathode) of inner radius ra and a coaxial cylindrical wire (the anode) of radius (see figure below) with a gas filling the space between the electrodes. Assume that the internal diameter of a Geiger-Mueller tube is 1.95 cm and that the wire along the axis has a diameter of 0.190 mm. The dielectric strength of the gas between the central wire and the cylinder is 1.25 x 106 V/m. Use the equation ain 2πrle= to calculate the maximum potential difference that can be applied between the wire and the cylinder before breakdown occurs in the gas. €0 Anode Cathode 148 X Your response differs from the correct answer by more than 10%. Double check your calculations. V Need Help? Read It

A Geiger-Mueller tube is a radiation detector that consists of a closed, hollow, metal cylinder (the cathode) of inner radius ra and a coaxial cylindrical wire (the anode) of radius (see figure below) with a gas filling the space between the electrodes. Assume that the internal diameter of a Geiger-Mueller tube is 1.85 cm and that the wire along the axis has a diameter of 0.195 mm. The dielectric strength of the gas between the central wire and the cylinder is 1.10 x 106 V/m. Use the equation 2 rlE = in to calculate the €0 maximum potential difference that can be applied between the wire and the cylinder before breakdown occurs in the gas. Cathode Anode Ⓡ

Two equal air-filled capacitors of Co- 15 µF are connected in series. A dielectric slab of constant K is inserted inside one of them to fully occupy the space between the conductors. The equivalent capacitance of the combination becomes Ceq™ 13.68 µF. Find the value of K.

Note: The value of a=0, b=5 and C=7.

estion 9. A cell membrane has a thickness of t = 80 nm, and a radius r = 15 µm. The relative dielectric constant is 2.5. Estimate the cell capacitance.