3 capacitance a model of a red blood cell portrays the cell as a spher
Question
3) [Capacitance]
A model of a red blood cell portrays the cell as a spherical capacitor,
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
100mV across the membrane. The membrane's thickness is estimated to be
100 nm and has a dielectric constant of 5.00.
(a) If an average red blood cell has a mass of 1.00x10-¹2kg, estimate the
volume of the cell and thus find its surface area. The density of blood is
1,100kg/m³.
(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 (number of electrons) does the surface charge represent? Take
electronic charge to be 1.6 x 10-1°C.