3. Recently unearthed discoveries in North and South American archaeological sites show that charcoal from ancient fires gave a ¹4℃ decay rate of 0.4 dpm/g. The 14C/¹2C ratio in living organisms is 1.3 x 10-¹2 with a decay rate of 15 dpm/g. What is the approximate age of the sample? The half-life of ¹4C is 5730 years.

The half‑lives of different medical radioisotopes are given in the table. If the initial amount of chromium‑51 is 133 mCi, how much chromium‑51 is left in the body after 84 days? Radioisotope Half‑life (days) arsenic‑74 18 iodine‑131 8 phosphorus‑32 14 chromium‑51 28

Which of the following is the CORRECT formula to calculate the half-life (t1/2) for a radioactive decay? Assume the rate constant is k and the initial concentration of the radioactive isotope is [N]o.    t1/2 = [N]o/k t1/2 = ln2/k t1/2 = 1/(k[N]o)

A sample of bone is subjected to radiocarbon dating. The current decay rate observed for its carbon-14 content is 11.2 disintegrations per minute per gram of carbon. What is the age (in years) of the bone? The half-life for carbon-14 is 5.73 x 103 yrs, and the decay rate for carbon-14 in living organisms is 14.3 disintegrations per minute per gram of carbon.

Radioactive vanadium-48 decays with a half-life of 16.0 days. a. What is the value of k in s? k = b. A sample contains 84.0 mg *°V. How many decay events will be produced in the first second? Assume the atomic mass of **V is 48.0 u. decays/s c. A chemist obtains a fresh sample of 48 V and measures its radioactivity. She then determines that to do an experiment, the radioactivity cannot fall below 25% of the initial measured value. How long does she have to do the experiment? days

The remnants of an ancient fire in a cave in africa showed a 146C decay rate of 3.9 counts per minute per grams of carbon. if the decay rate in C-14 in freshly cut wood, is 13.6 counts per mintue per gram of carbon, how many years ago did the campfire occur?

Archeologists continue to debate the arrival of the first humans in the Western Hemisphere. Radiocarbon dating of charcoal from a cave in Chile was used to establish the earliest date of human habitation in South America as 8700 years ago. This procedure involves comparing the 14C present in a sample of charcoal to the 14C present in a living tree of the same age. What fraction of the 14C initially present remained in the charcoal after 8700 years? The half-life of 14C is 5730 years. (Write the answer as a number with a decimal.)

The half-life of 14C is 5730 years, and the current decay rate in living organisms is 14.3 disintegrations per minute per gram of carbon (d.p.m./g C). What is the age (in years BP) of an artifact found to have a decay rate of 4.75 d.p.m/g C in 2013? IMPORTANT: When entering your answer: • Enter the number only (no units) • Do not leave any spaces • Report your number to the tens column (regardless of the significant figures) Correctly round your answer to the tens column (margin of allowed error is only ± 10, so always use un-rounded numbers in your calculations) Examples: 12340 or 5670 (include the zero in the units column, Canvas will add a comma for you)