Because of the chaotic motion ofmolecules in a gas the free paths of molecules have different values. If on the vertical axis we layoff the logarithm of the number of molecules whose free paths exceed a certain value `x` and on the horizontal axis the value of x, the graph representing the dependence of these two quantities is a straight line with a negative slope, `log N = logN_o - ax`. How can one find the free path of molecules using such a graph?