A model of a red blood cell portrays the cell as a spherical capacitor, a positively charged liquid sphere of surface area A separated from the surrounding negatively charged fluid by a membrane of thickness t. Tiny electrodes introduced into the interior of the cell show a potential difference of 100 mV across the membrane. The membrane's thickness is estimated to be 101 nm and has a dielectric constant of 5.00. (a) If an average red blood cell has a mass of 1.10 x 10-12 kg, estimate the volume of the cell and thus find its surface area. The density of blood is 1,100 kg/m³. (Assume the volume of blood due to components other than red blood cells is negligible.) volume m³ m² surface area (b) Estimate the capacitance of the cell by assuming the membrane surfaces act as parallel plates. (c) Calculate the charge on the surface of the membrane. How many electronic charges does the surface charge represent?

A capacitor consists of two large flat parallel plates. One plate has surface charge density 4.96 nC/m2 and the other has an equal but opposite surface charge density. The plates are spaced a distance 8.01 cm apart. Give the magnitude of the voltage (difference in electric potential) between the two plates. Answer in units of V.

An electronic flash unit for a camera contains a capacitor with a capacitance of 940 µF. When the unit is fully charged and ready for operation the potential difference between the capacitor plates is 430 V. What is the magnitude of the charge on each plate of the fully charged capacitor?  Group of answer choices 0.140 C 2.57 C 10.1 C  0.404 C

help

Two parallel-plate capacitors C, and C, are connected in parallel to a 12.0 V battery. Both capacitors have the same plate area of 4,10 cm? and plate separation of 2.65 mm. However, the first capacitor C, is filled with air, while the second capacitor C, is filled with a dielectric that has a dielectric constant of 4.00. (a) What is the charge stored on each capacitor? Q1 = pC Q2 = pC (b) What is the total charge stored on the parallel combination? PC Additional Materials

A potential difference exists between the inner and outer surfaces of the membrane of a cell. The inner surface is negative relative to the outer surface. If 1.25 x 10^-20 J of work is required to eject a positive sodium ion (Na+) from the interior of the cell, what is the magnitude of the potential difference between the inner and outer surfaces of the cell?

A potential difference of 75 mV exists between the inner and outer surfaces of a cell membrane. The inner surface is negative relative to the outer surface. How much work is required to eject a positive sodium ion (Na+) from the interior of the cell?

A parallel-plate capacitor in air has a plate separation of 1.58 cm and a plate area of 25.0 cm2. The plates are charged to a potential difference of 270 V and disconnected from the source. The capacitor is then immersed in distilled water. Assume the liquid is an insulator. (a) Determine the charge on the plates before and after immersion. before pC pC after (b) Determine the capacitance and potential difference after immersion. Cf = F AV = V (c) Determine the change in energy of the capacitor. nJ Need Help? Read It

A potential difference of 90 mV exists between the inner and outer surfaces of a cell membrane. The inner surface is negative relative to the outer surface. How much work is required to eject a positive sodium ion (Na+) from the interior of the cell?

The capacitance of an empty capacitor is 1.2 μF. The capacitor is connected to a 12-V battery and charged up. With the capacitor connected to the battery, a slab of dielectric material is inserted between the plates. As a result, 2.6 × 10–5 C of additional charge flows from one plate, through the battery, and onto the other plate. What is the dielectric constant of the material?