Question

If $Z$ is the total number of collisions which a gas molecule registers with others per unit time under particular conditions, then the collision frequency of the gas containing $N$ molecules per unit volume is :

• A. $\frac{Z}{N}$
• B. $NZ$
• C. $2NZ$
• D. $\frac{NZ}{2}$

Answer 1

Answer: (D)

$\frac{NZ}{2}$

Collision frequency is the number of molecular collisions per unit time per unit volume is collision frequency.

So total number of colliding molecules per unit time per unit volume is the product ofnumber of collisions (Z) and Number of molecules(N) that is $NZ$.

Each collision involves two molecules

So collision frequency $=\frac{NZ}{2}$.

Hence option D is correct.