15. The narrow beam attenuateon of an x-ray beam by a 0.5 mm thick lead foil is 91%. O21 10 Bleib s Is nim\\yo Cos at masd a. What percentage of the radiation will be attenuated by a 1.0 mm thick lead foil? Ignore beam hardening. Jon ob Do b. What percentage of the radiation will be attenuated by a 0.25 mm thick lead foil? nil s to vilansini andT 16 a. Describe two effects on the spectrum of increasing the filtration of a diagnostic energy x-ray beam. b. What is the purpose of added filtration for a diagnostic x-ray machine? airgib ingor 17. What is beam hardening, and why does it occur