Potassium-42 is a b emitter with a half-life of 12.36 h. Calculate
the fraction of this radionuclide remaining in a sample after 1, 10, 20, 30,
40, 50, 60, 70, and 100 h. Plot the fraction remaining versus time. Determine
the time required for the fraction to fall to 1%.
Identify X in each of the following nuclear reactions: