1. The problem statement, all variables and given/known data Calculate how many conduction electrons pass through a given area per second when a current of 1A flows. 2. Relevant equations Current density, j = i/A (i=current, A=cross sectional area) Current desntiy, j = nevD (n=no of electrons per unit volume, e=charge on electron, vD=drift velocity) 3. The attempt at a solution I've taken an element of volume of length vDt and cross-sect area, A. I've surmised then that the total number of electrons in that area will be N=nAvDt. All of those electrons will then cross a plane in 1 second, so i've equated j=i/A=nevD, and substituted n from the earlier (bold) equation - n=N/AvD. However, that produces a result of N=i/e=1/e ... doesn't look right! Help!!