Answer to Question #325188 in Physics for Belal

Question

The resting potential of the crab limb nerve is 89 mV. What is the

concentration of potassium ions inside the nerve, if it is 12mmol/1 outside?

Take the temperature equal to 20°C

Answer 1

The resting potential is given by

$$V=60\log\frac{[K^+]_o}{[K^+]_i}\;\rm(mV)$$

Hence, the concentration of potassium ions inside the nerve

$$[K^+]_i=[K^+]_o\times e^{-\frac{V}{60}}$$

$$[K^+]_i={12\:\rm mmol/L}\times e^{-\frac{89}{60}}=2.7\:\rm mmol/L$$