An X-ray beam has the photon energy of 1.2 Me and its intensity is reduced by 90% after

passing a water sample of 5 mm thickness. For the water sample, the molar mass is 18 g/mol and the density is I g/cm^3, here k = 0.3. Determine the interaction cross section per atom (in cm?).

(6 marks)

Express the values to 3 significant figures, if necessary.

B4. An X-ray beam has the photon energy of 1.2 MeV and its intensity is reduced by 90% after passing a water sample of 5 mm thickness. For the water sample, the molar mass is 18 g/mol and the density is 1 g/cm', here k = 0.3. Determine the interaction cross section per atom o (in cm2). (6 marks) Express the values to 3 significant figures, if necessary