1. The problem statement, all variables and given/known data Find the drift velocity in a copper fuse wire with a diameter of 0.22mm. The current is at 5A. Electronic charge is always 1.6*10-19 Number of de-localised electrons per cubic meter in copper = 1*10-19 2. Relevant equations I=Avnq Current = cross-sectional area*drift velocity*number of de-localised electrons*Electroic Charge 3. The attempt at a solution First i converted the diameter of 0.22mm into radius 0.11mm. Then using pi*r2 i have 3.8mm2. Then i converted this into SI to make it 3.8*10-3m2. So at this point here is the infomation i have. I=5A A=3.8*10-3m2 v= ? n= 1*1029 q=1.6*10-19 I then re-arranged the formula of I=Avnq to make v the subject. v= __I__ Anq Then putting in all the numbers i have... v= ______5______ 3.8*10-3m2 * 1*1029 * 1.6*10-19 Tapping this into my calculator got me the answer of 8.2*10-8ms-1 However this is crazy slow, i know drift velocity is very slow but not this slow. Looking at the answer in the back of the book, for somereason they put it in mm not m, 8.2mms-1. So this in SI should be 8.2*10-3ms-1. This means at some point in my calculations i am 1*105 wrong. Me and and friends doing this work have been struggling to find out why we are not getting the correct answer. I hope i made sence explaining this to you. We think our errors must be around finding the cross-sectional area, or we had the wrong infomation to begin, such as the number of de-localised atoms in a cubic meter of copper. Or just some mess up of the numbers along the way. Thanks to the people who can help us out here.