(T2) Ejercicio Radiactividad
Ejercicio 3.1 (a) In a sample of 20.000 atoms, if 400 decay in 8 seconds what is the radioactivity, measured in mCi, of the sample? Cada 8 segundos se desintegran 400, por lo que las desintegraciones por segundo serán: 400/8=50 Bq --> que equivale a 1'35 · 10 6 mCi (b) In order to produce a level of radioactivity of 1 mCi, how many nuclei of 99m Tc ( λ = 3'22·10 -5 s-1) must be present? What mass of the radiotracer does this correspond to? (Avogadro's number is 6.02· 10 23 ) 1 mCi = 3'7· 10 7 Bq (c) A radioactive sample of 99m Tc contains 10 mCi activity at 9 am. What is the radioactivity of the sample at 12 pm ofn the same day? 10 mCi = 3'7· 10 8 Bq 9 am - 12 pm --> 15 horas --> 54.000 segundos