Problem 6.237

The mean path length of alpha-particles in air under standard conditions is defined by the formula $R=0.98 \cdot 10^{-27} v_{0}^{3} \mathrm{~cm}$ where $v_{0}(\mathrm{~cm} / \mathrm{s})$ is the initial velocity of an alpha-particle. Using this formula, find for an alpha-particle with initial kinetic energy $7.0 \mathrm{MeV}:$ (a) its mean path length; (b) the average number of ion pairs formed by the given alphaparticle over the whole path $R$ as well as over its first half, assuming the ion pair formation energy to be equal to $34 \mathrm{eV}$.