Keerthana
Posted on

If the pressure in a closed vessel is reduced by drawing out some gas, the mean free path of the gas molecules will

a

increase or decrease depending on the nature of the gas

b

increase

c

remain unchanged

d

decrease

Answer : Option B
Explanation :

Mean free path of gas molecules is the average distance travelled by a molecule between two successive collisions. It is represented by λ

λ=2πd2n\lambda=\sqrt{2} \pi d^{2} n

where d = diameter of molecule and n = number of molecules per unit volume of the gas.

Also

λ=KBT2πd2P\lambda=\frac{\mathrm{K}_{\mathrm{B}} \mathrm{T}}{\sqrt{2} \pi \mathrm{d}^{2} P}

where KB\mathrm{K}_{\mathrm{B}} is Boltzmann constant; P is the pressure and T is temperature of the gas. So Mean

free path of gas molecules is inversely proportional to the pressure of the gas.

As per the question, the pressure in the closed

vessel is reduced by drawing out some gas. So

as per the equation, the mean free path of the

gas molecules will increase.

Rate This:
NaN / 5 - 1 votes
Profile photo for Dasaradhan Gajendra