# Question

At present, a radioactive beta source with a long half-life has an activity of 20 mCi.

(a) What is the present decay rate in decays per second?

(b) Assuming that one beta particle is emitted per decay, how many are currently emitted per minute?

(a) What is the present decay rate in decays per second?

(b) Assuming that one beta particle is emitted per decay, how many are currently emitted per minute?

## Answer to relevant Questions

The half-life of a radioactive isotope is known to be exactly 1 h. (a) What fraction of a sample would be left after exactly 3 h: (1) one-third, (2) one-eighth, or (3) one-ninth? (b) What fraction of a sample would be left ...Carbon-14 dating is used to determine the age of some unearthed bones. (a) If the activity of bone A is higher than that of bone B, then bone A is (1) older than, (2) younger than, (3) the same age as bone B. Explain your ...In 1898, Pierre and Marie Curie isolated about 10 mg of radium-226 from eight tons of uranium ore. If this sample had been placed in a museum, (a) How much of the radium would remain in the year 2109? (b) How many radium ...35Cl and 37Cl are two isotopes of chlorine. What are the numbers of protons, neutrons, and electrons in each if (a) The atom is electrically neutral, (b) The ion has a –2 charge, and (c) The ion has a +1 charge? The mass of 84Be is 8.005 305 u. (a) Which is less, the total mass of two alpha particles or the mass of the 8Be nucleus? (b) Which is greater, the total binding energy of the 8Be nucleus or the total binding energy of two ...Post your question

0