"Mean Free Path" is the average distance travelled by a moving particle (such as an atom, a molecule, a photon) between successive impacts (collisions) which modify its direction or energy or other particle properties.
Applicable units are those of quantitykind:Length
http://en.wikipedia.org/wiki/Mean_free_path
"Mean Free Path" is the average distance travelled by a moving particle (such as an atom, a molecule, a photon) between successive impacts (collisions) which modify its direction or energy or other particle properties.
http://www.iso.org/iso/catalogue_detail?csnumber=31895
http://www.iso.org/iso/catalogue_detail?csnumber=31894