An empirical expression for distance that a particles can travel in air, called the range, is R(cm) = (0.31)E^3/2 for E in MeV and 4 < E < 7 MeV.

(a) What is the range in air of a 5 MeV a particle? 

(b) Express this range in g/cm², using ρ = 1.29 x 10^-3 g/cm³ for air.

(c) Assuming the range in g/cm² is the same as that of aluminum (ρ = 2.70 g/cm³), find the range in aluminum in cm for a 5 MeV a particle.