Final answer:
The physical half-life of N-13 ammonia is not specified in the reference, but the concept of half-life refers to the time it takes for half of a radioactive sample to decay. N-13 has a half-life of approximately 10 minutes, which is important in PET imaging applications.
Step-by-step explanation:
The physical half-life of N-13 ammonia is not provided directly in the reference information. However, we can discuss the concept of half-life in the context of radioactive decay. The half-life is the time it takes for half of the radioactive nuclei in a sample to decay. For instance, if we consider carbon-14 (C-14), its half-life is approximately 5730 years, which is useful in dating procedures for organic artifacts. In the case of hydrogen-3 (tritium), the half-life is 12.3 years, and it would take a significant amount of time for 99.0% of a sample to decay, based on its half-life.
If we apply this concept to N-13 ammonia, which the student has asked about, we could calculate the amount of N-13 remaining after a given period if we knew its half-life. However, typically for PET imaging (a practical application of N-13 ammonia), the half-life of N-13 is known to be approximately 10 minutes. This means if you started with a certain amount of N-13 ammonia, after about 10 minutes, you would expect to have half the original amount remaining due to its radioactive decay.