大学物理（热学）. Mean Free Path Diffusion, Thermal conductivity, and Viscosity. 2006-10-12. n i the number of molecules of. in. v y v y + d v y. Equilibrium distribution. d n is the number of molecules. near v. Meaning of d n / N. among N molecules , how many are near v.
ni the number of moleculesof
vy vy + dvy
dn isthe number of molecules
Meaning of dn/N
amongN molecules, how many are near v
probability that one molecule is near v
proportional to dvx ...
The solution is
The probability should be normalized
Maxwell velocity distribution
Most probable speed
For one molecule, what speed is most possible?
Among N molecules, what is the speed most molecules have in unit interval?
Heat transfer :
conduction convection thermal radiation
r = 1.12×10−10m