Question
According to the molecular kinetic theory of gases, what is the mean free path?
✓
Answer
Mean free path : The distance that gas molecules travel before colliding with another molecule is called mean free path. The value of free path may be different in different collisions. We can understand in another way like this.
The avarage distance travelled by a molecule between two consecutive collisions is called mean free path. Let us represent this $\bar{\lambda}$
Mean free path $=\frac{\text { Total distance travelled }}{\text { Number of collisions }}$
If any molecule travel the distance $\lambda_1, \lambda_2, \lambda_3, \ldots \ldots \ldots \lambda_{ N }$ after $\text {t}$ time with $\text {N}$ different collisions then mean free path value will be
$\bar{\lambda}=\frac{\lambda_1+\lambda_2+\lambda_3 \ldots \ldots \ldots \lambda_{ N }}{ N }$
Average free path is inversely proportional to the density of the gas and proportional to the mass of the molecule
$\bar{\lambda} \propto \frac{1}{\rho}$
Free path depend on temperature and pressure that means
$\begin{array}{l}\quad \quad\quad\bar{\lambda} \propto T \\\text {and}\quad \bar{\lambda} \propto \frac{1}{\rho}\end{array}$
The avarage distance travelled by a molecule between two consecutive collisions is called mean free path. Let us represent this $\bar{\lambda}$
Mean free path $=\frac{\text { Total distance travelled }}{\text { Number of collisions }}$
If any molecule travel the distance $\lambda_1, \lambda_2, \lambda_3, \ldots \ldots \ldots \lambda_{ N }$ after $\text {t}$ time with $\text {N}$ different collisions then mean free path value will be
$\bar{\lambda}=\frac{\lambda_1+\lambda_2+\lambda_3 \ldots \ldots \ldots \lambda_{ N }}{ N }$
Average free path is inversely proportional to the density of the gas and proportional to the mass of the molecule
$\bar{\lambda} \propto \frac{1}{\rho}$
Free path depend on temperature and pressure that means
$\begin{array}{l}\quad \quad\quad\bar{\lambda} \propto T \\\text {and}\quad \bar{\lambda} \propto \frac{1}{\rho}\end{array}$
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