This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
The concentration of a negative ion is 100 mMoUL extracellular and 10 mMo1/1 intracellular. What will be the Nernst potential for this ion? 
Select and explain. 
A. --10 mV, B. +10 mV, C. --61 mV, D. +61 mV
C: --61 mV
Answer: C: --61 mV 
Explanation: Ans: C. --61 mVRef: Ganong 25Ie p9, p24Ie p9-10; Guyton 13Ie p61Ek = 61.5 log Ci/CeIntracellular concentration Ci = 100Extracellular concentration Ce = 10EK = 61 C log100/10 = -61 mV.