Mean free path is a term inherently tied to deposition by evaporation. Which of the following is the correct definition for mean free path:
It is the average distance travelled by the evaporated source to the substrate.
It is the distance travelled by a moving particle between two successive collisions.
It is the trajectory of the path followed by a free moving particle
None of the above.
Answers
Answer:
It is the distance travelled by a moving particle between two successive collisions
Explanation:
In physics, the 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
Imagine a beam of particles being shot through a target, and consider an infinitesimally thin slab of the target. The atoms (or particles) that might stop a beam particle are shown in red. The magnitude of the mean free path depends on the characteristics of the system. An expression for the MFP is
ℓ = (σn)^-1
where ℓ is the mean free path, n is the number of target particles per unit volume, and σ is the effective cross-sectional area for collision.
Definition for mean free path:
It is the distance traveled by moving particle between two successive collisions.
Option B
Explanation:
All material is composed of ions, atoms, molecules. These small matters are in rapid motion according to "kinetic theory" of matter. These particles rapidly collide with each other while they move.
Mean free path is the distance travelled by moving particle between two successive collisions. In a collision, particles transmit energy to each other. Hence this varies from objects to objects. Mean free path also depends on Boltzmann constant of classical physics.