= (-1) in 2A 3- (20 points) Using the following values for the microscopic scattering cross sections for hydrogen and oxygen, o' = 20.1 barns and 0 = 3.8 barns respectively, and the definition of average lethargy gain per collision = 1 calculate average lethargy gain per collision for water H20 Average lethargy gain per collision of a substance containing more than one material is given as: = ($651251 +22,2 + . En sn) where 1, 2. shows different atom species