What is the mean free time between collisions for electrons in an iron and aluminum wire?
Answer
Use the following formula to find the mean free time. mo ne Here, m is the mass of the electron the charge of the electron, n s the density of conduction e 1s electrons and o is the conductivity The density of conduction electrons in the iron wire is ircn is denstiy of iron NAis the avgadronumber ( (Pra) A A is the atomicmass of iron 6x1023 7874kg/ m 55.845u -8.46x1028 3 m The mean free time for iron is (9.1x103 kg) (1x10'nm1) (8.46x10 m1.6x10-1" C) 4.2x1015 S The density of conduction electrons in the aluminum wire is Pro is denstiy of Al n (Pon) NA is the avgadro number A is the atomic mass of Al 6.022x1023 (2710kg/m3) 26.98 u 6x1028 m The mean free time for iron is (9.1x103 kg) (3.5x10'r m1) (6x10 m3(1.6x10-9 c) 28 2.1x1014 S