All Problems

Kinetic theory of gases. Boltzmanns Law and Maxwell distribution

Problem 2.101

From the conditions of the foregoing problem find the number of molecules reaching a unit area of a wall with the velocities in the interval from \(v\) to \(v+d v\) per unit time.

Reveal Answer
dv=θ=0π/2dn(dΩ/4π)vcosθ=π(m/2πkT)3/2emv2/2hTv3dvd v=\int_{\theta=0}^{\pi / 2} d n(d \Omega / 4 \pi) v \cos \theta=\pi(m / 2 \pi k T)^{3 / 2} \mathrm{e}^{-m v 2 / 2 h T} v^{3} d v