Consider propagation of neutrinos (produced in the interaction of cosmic rays with air ) through the earth. what fraction of neutrinos with energy 10 gev will be absorbed when passing through the earth's center. hint: the fraction is very small so you can use the taylor series expan- sion for n )no exp(x) to calculate probability of interaction. to perform the calculation use the particle data book on the web (see syllabus for pointer) to find the plot for neutrino - nucleon cross section. use radius of the earth from the web and take average density of the earth equal 6 g/cm3 to calculate cross section of interaction with nuclei in the media treat the media as a collection of free nucleons