What particle (a particle, electron, or positron) is emitted in the following radioactive decays? (a) 27 14SiS 27 13 Al; (b) 238 92U S 234 90Th; (c) 74 33As S 7434Se.

Measurements on a certain isotope tell you that the decay rate decreases from 8318 decays/min to 3091 decays/min in 4.00 days. What is the half-life of this isotope?

The unstable isotope 40K is used for dating rock samples. Its half-life is 1.28x10^9 y. (a) How many decays occur per second in a sample containing 1.63x10^-6 g of 40K? (b) What is the activity of the sample in curies?

The common isotope of uranium, 238U, has a halflife of 4.47x10^9 years, decaying to 234Th by alpha emission. (a) What is the decay constant? (b) What mass of uranium is required for an activity of 1.00 curie? (c) How many alpha particles are emitted per second by 10.0 g of uranium?

Radioactive isotopes used in cancer therapy have a 'shelf-life,' like pharmaceuticals used in chemotherapy. Just after it has been manufactured in a nuclear reactor, the activity of a sample of 60Co is 5000 Ci. When its activity falls below 3500 Ci, it is considered too weak a source to use in treatment. You work in the radiology department of a large hospital. One of these 60Co sources in your inventory was manufactured on October 6, 2011. It is now April 6, 2014. Is the source still usable? The half-life of 60Co is 5.271 years.

The atomic mass of 14C is 14.003242 u. Show that the b- decay of 14C is energetically possible, and calculate the energy released in the decay.

What nuclide is produced in the following radioactive decays? (a) a decay of 239 94 Pu; (b) b- decay of 24 11Na; (c) b+ decay of 15 8O.

(a) Is the decay nS p + b- + ve energetically possible? If not, explain why not. If so, calculate the total energy released. (b) Is the decay pS n + b+ + ve energetically possible? If not, explain why not. If so, calculate the total energy released.

The most common isotope of uranium, 238 92U, has atomic mass 238.050788 u. Calculate (a) the mass defect; (b) the binding energy (in MeV); (c) the binding energy per nucleon.