// calculating the length of mean free path clc; T=273+20; P=101.3*10^3; mfp=22.7*10^-6*T/P; disp(mfp,'length of mean free path when pressure is one atmospheric pressure(m)') P=133; mfp=22.7*10^-6*T/P; disp(mfp,'length of mean free path when pressure is one torr(m)') P=133*10^-3; mfp=22.7*10^-6*T/P; disp(mfp,'length of mean free path when pressure is one micrometer of Hg(m)') P=249.1; mfp=22.7*10^-6*T/P; disp(mfp,'length of mean free path when pressure is one inch of water(m)') P=133*10^-6; mfp=22.7*10^-6*T/P; disp(mfp,'length of mean free path when pressure is 10^-3 micrometer of Hg(m)')