# physics

posted by Jason

A typical cell membrane is 8.0 nm thick and has an electrical resistivity of 1.3 × 107Ω.m.
(i) If the potential difference between the inner and outer surfaces of a cell membrane is 75 mV, how much current ﬂows through a square area of membrane on a side?
(ii) Suppose the thickness of the membrane is doubled, but the resistivity and potential difference remain the same. Does the current increase or decrease? By what factor?

1. Damon

R = 1.3 * 10^7 * 8 * 10^-9 ohms/m^2
i = V/R

b. Same V, double R, half i

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