1. How many helium atoms are emitted by 1 gram of Argon?

2. The activity of a sample prepared decreases 1.5 times after 6.0 months. Find its half-life period.

3. Find the half life and mean life times of Co^{55} if its activity is known to decrease 5.0% per day. (consider the decay product to be nonradioactive.)

4. The half lifes of two nuclides are 20 days and 6 years respectively. Calculate their specific activities.

5. The half life of a radioactive cobalt isotope is 71.3 days. What fraction of this sample are decayed/left during/after 3 months?

6. How may alpha and beta disintegrations does U^{238} undergo before forming a stable Pb^{206}?

7. If Ra^{226} decays 5 alpha and 4 beta particles, what is the isotope formed?