1. Determine the mean free path of a H2 molecule (σH2 = 0.27 * 10^-18 m2) at 0.1 bar pressure at 300 K.
2. An electron travels through the H2 (g). Calculate the electron mean free path in H2(g) at 0.1bar and 300K. Assuming the diameter of the electron is very nearly zero, and that the electron has the same relative speed as the H2 molecules.
3. Calculate the order of magnitude to which the pressure must be reduced so that the electron beam attenuation by electron - H2 collisions is 1/e over the 0.5m length for a cathode ray tube to deliver electrons to a screen over a distance of 0.5m. The residual gas in the tube is H2.