In an infinite homogeneous medium containing a uniformly distributed radionuclide source emitting radiation energy at a rate of E MeV cm-3s-1, energy must be absorbed uniformly by the medium at the same rate. Consider an infinite air medium with a density of 0.0012 g/cm3containing tritium (half-life 12.33 y and emitting beta particles with an average energy of 5.37 MeV/decay) at a concentration of 2.3pCi/L. What is the air-kerma rate (Gy/h)?