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Type your question here A model of a red blood cell portrays the cell as a capac

ID: 2279287 • Letter: T

Question

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A model of a red blood cell portrays the cell as a capacitor with two spherical plates. It is a positively charged conducting liquid sphere of area A, separated by an insulating membrane of thickness t from the surrounding negatively charged conducting fluid. Tiny electrodes introduced into the cell show a potential difference of 100 mV across the membrane. Take the membrane's thickness as 100 nm and its dielectric constant as 5.00. Assume that a typical red blood cell has a mass of 1.11 times 10-12 kg and density 1,100 kg/m3. Calculate its volume and its surface area. Find the capacitance of the cell. Calculate the charge on the surfaces of the membrane. How many electronic charges does this charge represent?

Explanation / Answer

volume=mass/density=1.009*10^(-15) m^3


so (4/3)*pi*radius^3=volume


radius=6.22 um



so area=4*pi*radius^2=4.865*10^(-10) m^2


b)capcitance=5*8.854*10^(-12)*area/thickness=0.2153 pF


c)charge=capacitance*voltage=2.153*10^(-14) coloumb


no of electrons=charge/(1.6*10^(-19))=134.615*10^3