Mean Free Path and RMS Speed
Mean Free Path and RMS Speed: Overview
This topic contains concepts like Time for Successive Collisions between Walls, and Mean Free Path.
Important Questions on Mean Free Path and RMS Speed
The mean free path of molecules of a certain gas at STP is , where is the diameter of the gas molecules. While maintaining the standard pressure, the mean free path of the molecules at is approximately:

In a gas at STP, if is the number density of the molecules and is the radius of the molecule, then the mean free path of the molecule is inversely proportional to

The collision frequency of nitrogen molecule in a cylinder containing at pressure and temperature is approximately: (Take radius of a nitrogen molecule is )

Time for successive collisions between walls :-
(ii) Time for two successive collision between the walls is.

Time for successive collisions between walls ;-
(i) When there is collision between two walls then charge in momentum per second is .

Derive the formula for time for successive collision between the walls of the container with the molecule.

For a gas with number of molecules per unit volume, Suppose the molecules of a gas are spheres of diameter the average speed of each molecule is . The time between two successive collisions is on the average

The mean free path of a gas sample is given by:

If the temperature and pressure of a gas is doubled the mean free path of the gas molecules

For a molecule of an ideal gas, the number density is and the mean free path is . The diameter of the gas molecule is

Consider an ideal gas confined in an isolated closed chamber. As the gas undergoes an adiabatic expansion, the average time of collision between molecules increases as , where is the volume of the gas. The value of is :-

Define the following
Mean free path

Define the following
Free path

A container is divided into two equal part I and II by a partition with small hole of diameter d. The two partitions are filled with same ideal gas, but held at temperature and by connecting to heat reservoirs. Let and be the mean free paths of the gas particles in the two parts such that and Then is close to.

At any instant, the position and velocity vectors of two particles are respectively. They will collide if :

In the following a statement of Assertion is followed by a statement of Reason.
Assertion: Mean free path of a gas molecule is inversely proportional to the density of gas.
Reason: Path of a gas molecule between two adjacent collision is straight line.

Consider an ideal gas confined in an isolated closed chamber. As the gas undergoes an adiabatic expansion, the average time of collision between molecules increases as , where is the volume of the gas. The value of is

Which of the following is/are correct regarding mean free path ?

Which of the following is/are correct regarding mean free path ?

Air becomes conducting when the pressure ranges between
