Chapter 18, Problem 47P

BIO EST Axon capacitance The long thin cylindrical axon of a nerve carries nerve impulses. The axon can be as long as 1 m. (a) Estimate the capacitance of a 1.0-m-long axon of radius $\text{4}\text{.0 }\times {\text{10}}^{\text{-6}}\text{m}$ with a membrane thickness of $\text{8}\text{.0 }\times {\text{10}}^{\text{-9}}\text{m}$. The dielectric constant of the membrane material is about 6.0. (b) Determine the magnitude of the charge on the inside (negative) and outside (positive) of the membrane wall if there is a 0.070-V potential difference across the wall. (c) Determine the energy stored in this axon capacitor when charged.