Question

(496) Using the following figure, A) determine the energy released by the fission of U-235 (U- 235 becomes Cs-137 and Sr-96, plus neutrons and energy). B) How many neutrons are produced by this specific fission? 2, 0 20 4060 100 20 140180 200 220 240 MASS NUMBER(A)

Answer 1

The energy released is equal to the difference in binding energy of products and reactants. i.e., B.E(Product) - B.E(Reactants) = > B middot energy of reactants = B.E of U^235 B middot energy of U^235 = B middot energy pre nucleon for U^235 times No.of of nucleons. No.of of nucleons in U^235 = No of nucleons + No of protons {Basically mass number} = 235 B middot energy per nucleon tilde 7.6 M_r V(from curve) So, B middot energy of U^235 = 235 times 7.6 = 1786 M_r V = > B middot energy of product = B.E of -137 + B.E of - 96 = (137 times 8.4) + (96 times 8.8) = 1150.8 + 844.8 = 1995.6 M_r V So, energy released = 1995.6 - 1786 = 209.6 M_r V B middot energy per nuclear is taken from curve and is an approximate value as the curve is act using pressure. = > No. of neutrons released can be calculated by raw of conservation of mass i.e., mass of products = mass of reactants. 235 = 137 +

Note- I have taken the values for binding energy per nucleon from the given curve. Since the curve is not very precise, there might be some deviation from the actual value.