A model of a red blood cell portrays the cell as a sphericalcapacitor, a positively charged liquid sphere of surface areaA separated from the surrounding negatively charged fluidby a membrane of thickness t. Tiny electrodes introducedinto the interior of the cell show a potential difference of 100 mVacross the membrane. The membrane's thickness is estimated to be103 nm and has a dielectric constant of 5.00.
(a) If an average red blood cell has a mass of 1.10 ✕10−12 kg, estimate the volume of the cell and thus findits surface area. The density of blood is 1,100 kg/m3.(Assume the volume of blood due to components other than red bloodcells is negligible.)
| volume    | m3 |
| surface area    | m2 |
(b) Estimate the capacitance of the cell by assuming the membranesurfaces act as parallel plates.
F
(c) Calculate the charge on the surface of the membrane.
C
How many electronic charges does the surface charge represent?
