Radium-226, 226Ra, undergoes an alpha decay. The current sample of Radium-226 has an initial activity of 5.50 x 10¹0 Bq. (a) Identify the daughter nucleus by name, nucleon number, atomic number and neutron number. (b) What is the decay constant? (c) How many radioactive nuclei were initially present in the sample? (d) How long will it take the sample to reach an activity of 5.00 × 10¹0 Bq?

Question 1. Tritium has a half - life of 12.33 years. What fraction of the nuclei in a tritium sample will remain (a) after 5.00 yr? (b) after 10.0 yr? (с) after 123.3 yг?

A sample of radioactive isotope is found to have an activity of 110 Bq imediately after it is pulled from the reactor that formed the isotope. Its activity 1 h, 20 min later is measured to be 89 Bq. Find the decay constant of the sample. Answer in units of h-. Find the half-life of the sample. Answer in units of h. How many radioactive nuclei were there in the sample initially?

The half-life of 1311 is 8.04 days. (a) Convert the half-life to seconds. S (b) Calculate the decay constant for this isotope. S-1 (c) Convert 0.570 μCi to the SI unit the becquerel. Bq (d) Find the number of 13¹1 nuclei necessary to produce a sample with an activity of 0.570 μCi. 1311 nuclei (e) Suppose the activity of a certain 13¹1 sample is 6.90 mCi at a given time. Find the number of half-lives the sample goes through in 40.2 d and the activity at the end of that period. (Enter your answer for the number of half-lives to at least one decimal place.) half-lives mCi