ممكن حل
 

_ If 1mCi of a radionuclide is adequately shielded by 5 HVLs of a shielding material, how many HVLs are needed to provide equal shielding for (a) 5mCi and (b) 8mCi?

_ There is a 75% chance that a monoenergetic photon beam will be attenuated by 4mm of lead. What is the HVL of lead for the photon?