Question

41. | An investigator collects a sample of a radioactive isotope with an activity of 370,000 Bq. 48 hours later, the activity is 120,000 Bg. What is the half-life of the sample? 207 . 1 22

Answer 1

Initial Activity of sample Ao = 370,000 Bq. after t= 40 hr the Activity is A = $ 20,000 Bq let the half life is Tola By relation it A = Ao e te decay constant 120000 = 370000 ett 12= 37e-it taking log at base e In 12 = ln 37+ (-xt) enes Ata en 37-en12 = 3.61- 2148 = 2.13 48 x=0.0235 hit 1=0.0235 hrs and 1= 0.693 T/2 = 0,693 T3/2 Top = 0.693 = 29.489 hy 0.0235 T = 29.49 hr approx