mean free path

Physics, Chem. (in a collection of moving particles)the average distance that a particle travels between successive collisions with other particles.

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      average distance an object will move between collisions. The actual distance a particle, such as a molecule in a gas, will move before a collision, called free path, cannot generally be given because its calculation would require knowledge of the path of every particle in the region. The probability (dP) that a molecule will move a distance between two points (x and x + dx) without collision is proportional to an exponential factor; that is, dP = e-x/μdx, in which e is the base of natural logarithms. The constant μ is the mean free path and is the average (mean) distance traveled by a molecule between collisions. The mean free path of an oxygen gas molecule under a pressure of 1 atmosphere at 0° C is about 6 × 10-6 cm (2 × 10−6 inch).

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Universalium. 2010.

Look at other dictionaries:

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  • mean free path — noun Date: 1879 the average distance traversed between collisions by particles (as molecules of a gas or free electrons in metal) in a system of agitated particles …   New Collegiate Dictionary

  • mean free path — noun the average distance travelled between two similar events; especially by molecules in a gas or liquid, electrons or phonons in a crystal or neutrons in a moderator …   Wiktionary

  • mean free path — noun 1. the average distance travelled by a particle, atom, or molecule between collisions with other particles. 2. the average distance travelled by a soundwave between successive reflections …   Australian English dictionary

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