Register to reply

Drude theory: Probablity of collision of electron per second

by Aniket1
Tags: collision, drude, electron, probablity, theory
Share this thread:
Feb19-13, 11:43 AM
P: 45
The Drude theory assumes the probability that an electron makes a collsion in a second with probabilty 1/ζ where ζ is the relaxation time. Since ζ can be any positive number, the probability can get greater than 1.
What does this mean?
Phys.Org News Partner Physics news on
Organic photovoltaic cells of the future: Charge formation efficiency used to screen materials
Promising ferroelectric materials suffer from unexpected electric polarizations
Structure of certain types of beetle shells could inspire brighter, whiter coatings and materials
Feb19-13, 05:45 PM
Sci Advisor
P: 6,058
Caveat: I know nothing about Drude theory. However in general when talking about relaxation time, the probabilities involved usually have an exponential form. It might mean that the probability that the electron does not collide before time t is e-t/ζ.
Jano L.
Feb21-13, 09:57 AM
PF Gold
P: 1,162
Yes, that seems right. Another way to understand it: imagine the collisions as random process, for which you know only that on average you get 1/τ collisions per unit time. The exponential probability follows, if I remember well.

Jano L.
Feb21-13, 10:00 AM
PF Gold
P: 1,162
Drude theory: Probablity of collision of electron per second

For example: if we expect 10 collisions per second, the probability that after one collision the second one will come after time longer than ##t##, comes out as


and decays to zero with time (the longer we wait, the more probable we will get collision in next instant).

Register to reply

Related Discussions
Photon-photon collision - electron-anti electron pair creation Introductory Physics Homework 4
Drude Theory of Metals Poisson Distribution Problem Advanced Physics Homework 0
Drude and Sommerfeld theory Atomic, Solid State, Comp. Physics 3
Drude model and electron mean free path? Advanced Physics Homework 0
Is Free-electron model := Drude Model (of metals) ? Atomic, Solid State, Comp. Physics 2