Question

(a) 40K, which can undergo both β+ and β-decay, decays by β-decay with a branching ratio of 89%. One gram of natural potassium (molar mass: 39.1 gm/mol) emits 1700 per minute from this decay, and 40K comprises 0.0118% of natural potassium. 10 Calculate the half-life of 40K b) Some of the particle interactions shown below are correct, others are incomplete (you may assume all are energetically possible). With the aid of the accompanying table of lepton properties, use conservation of baryon number, lepton number, and electric charge to supply one or (if necessary to satisfy a second conservation law) two missing particles to correct the right-hand sides of those interactions that you identify as incomplete. Missing particle(s) are always leptons or nucleons 10 e, ve+1 (iv) Ve +e n (v) + + ve 0

Answer 1

2 a) 2 ( ch吖ge is not earore& those (l() と で toh le ptom conserve。 井 in "not で Le. , o 牪in not Conserved) A -1 2 -1 2. e inte sa sion)

CLe (nJm isnot

6 .023 x 103 atoms f 21.3333333 ): 83934 x 10-21 SCc1. 6.693 S.G13 2 2 sec 39 34 x 10-21 ,