Chapter 18, Problem 62GP

* BIO Energy stored in axon electric field An axon has a surface area of $\text{5 }\times {\text{ 10}}^{\text{-6}}{\text{m}}^{\text{2}}$ and the membrane is $\text{8 }\times {\text{ 10}}^{\text{-9}}\text{m}$ thick. The dielectric constant of the membrane is 6. (a) Determine the capacitance of the axon considered as a parallel plate capacitor. (b) If the potential difference across the membrane wall is 0.080 V, determine the magnitude of the charge on each wall. (c) Determine the energy needed to charge that axon capacitor. (d) Determine the magnitude of the $\stackrel{\to }{E}$ field across the membrane due to the opposite sign charges across the membrane walls. (e) Calculate the energy density of that field. of Multiply the volume of space occupied by that field by the volume of the membrane to get the total energy stored in the field. How do the answers to (c) and of compare?