Figure 42-19 shows the decay of parents in a radioactive sample. The axes are scaled by and . What is the activity of the sample at?
The activity of the sample at t = 27s is 60 Bq.
Write the formula for undecayed sample remaining after a given time, as follows:
Write the formula for the rate of decay:
Here, is the disintegration constant, N is the number of undecayed nuclei.
The number of atoms present initially at t = 0 is . From Fig. 42-19, determine that the number is halved at t = 2s. Thus, using equation (i), determine the disintegration constant of the sample as follows:
Now, using this value in equation (i), determine value of the remaining nuclei of the radioactive sample at as follows:
Now, the activity of the sample at the given time is given using the above values in equation (ii) as follows:
Hence, the activity of the sample is 60 Bq.
The radionuclide decays to as described by Eq. 42-24. In a particular decay event, an 1.71 MeV electron is emitted, the maximum possible value. What is the kinetic energy of the recoiling atom in this event? (Hint: For the electron it is necessary to use the relativistic expressions for kinetic energy and linear momentum. The atom is non-relativistic.)
94% of StudySmarter users get better grades.Sign up for free