1. The problem statement, all variables and given/known data Nerve signals in the body occur when a small voltage, called an action potential, is applied across the membrane of a cell. When this action potential is applied across a region of the cell membrane called an ion channel, current in the form of moving potassium ions will be established across the cell. If, during an action potential of 90 mV, a single ion channel with a resistance of 1 G[PLAIN]http://loncapa.mines.edu/adm/jsMath/fonts/cmr10/alpha/100/char0A.png, [Broken] is opened for 1[PLAIN]http://loncapa.mines.edu/adm/jsMath/fonts/cmmi10/alpha/100/char3A.png2 [Broken] ms, approximately how many singly-ionized potassium ions travel through the channel during this time? 2. Relevant equations I = n*q*Vd*A 3. The attempt at a solution I first converted 90mV to 90E-3V. Then I convert 1GOhm to 1E9 Ohm. Then I converted 1.2 ms to .0012 s. I'm assuming I'm solving for "n" in the equation, so did V/R to find I (90E-3/1E9) I divided that by the fundamental charge, 1.602E-19 (*note, I also used simply a "1" here with no luck either) times time. I got 4.68E4, and other multitudes of 10, as my answer with no luck. And it's a practice exam so I shouldn't have to google anything (i.e. the area of an ion channel?). I also tried using J=n*q*Vd and J=0.5*Q/V, making the assumption my Q's could cancel. No cigar.