Answer Happy

Use the worked example above to help you solve this problem. The half-life of the radioactive nucleus 22Ra is 1.6x103 yr. If a sample initially contains 3.14 x 1016 such nuclei, determine the following: (a) the initial activity in curies 3.68e8 x Your response differs significantly from the correct answer. Rework your solution from the beginning and check each step carefully. uci (b) the number of radium nuclei remaining after 4.1x103 yr 5.32e15 nuclei (c) the activity at this later time 0.0745 Your response differs significantly from the correct answer. Rework your solution from the beginning and check each step carefully. PCI EXERCISE HINTS: GETTING STARTED 1 I'M STUCK! Use the values from PRACTICE IT to help you work this exercise. (a) Find the number of remaining radium nuclei after 3.00 x103 yr. N = 3.89e16 x As the radioactive material decays, will the number of radioactive nuclei increase or decrease? Why? nuclei (b) Find the activity at this time. R = 18.71 X As the radioactive material decays, will the activity of the sample increase or decrease? Why UCI