A gas at 300K has pressure 4×10−10N m−2. If kB=1.38×10−23J K−1, the number of molecules per cm3 is of the order of.
Given parameters are
P=4×10−10Nm−2
T=300K
V=1cm3=10−6m3
N = No. of molecules
Boltzmann’s constant =kB=1.38×10−23JK−1
From the ideal gas law, we have
PV=NkBT
N=PVkBT
Substituting the values, we get
N=4×10−10×10−61.38×10−23×300
N=0.967×105
N≃105
Thus option B is correct.