Question 4. A synthetic radioisotope is freshly prepared in a lab that has an ac- ivity of 10.0 mCi. If the activity of the radioisotope changes to 8.00 mCi, in 5.00 h, a) What is the decay constant and half-life of the radioisotope in seconds? b) How many atoms of the radioisotope were contained in the freshly prepared sam- ple? (c) What is the sample's activity in mCi 40.0 h after it is prepared?

Iodine-125 (¹251) is used to treat, among other things, brain tumors and prostate cancer. It decays by gamma decay with a half-life of 54.90 days. Patients who fly soon after receiving ¹25I implants are given medical statements from the hospital verifying such treatment because their radiation could set off radiation detectors at airports. If the initial decay rate (or activity) was 522 µCi, what will the rate be after 377.0 days? decay rate: JCi How many months after the treatment will the decay rate be reduced to 16.5% of the original value? Assume months of 30 days. months:

e half-life of 131I is 8.04 days.(a) Convert the half-life to seconds. s (b) Calculate the decay constant for this isotope. s−1 (c) Convert 0.550 ?Ci to the SI unit the becquerel. Bq (d) Find the number of 131I nuclei necessary to produce a sample with an activity of 0.550 ?Ci. 131I nuclei (e) Suppose the activity of a certain 131I sample is 6.50 mCi at a given time. Find the number of half-lives the sample goes through in 40.2 d and the activity at the end of that period. (Enter your answer for the number of half-lives to at least one decimal place.)half-livesmCi

The half-life of 222Rn is 3.82 days. (a) Convert the half-life to seconds. (b) Calculate the decay constant for this isotope. (c) Convert 0.520 ?Ci to the SI unit the becquerel. (d) Find the number of 222Rn nuclei necessary to produce a sample with an activity of 0.520 ?Ci. (e) Suppose the activity of a certain 222Rn sample is 6.10 mCi at a given time. Find the number of half-lives the sample goes through in 40.2 d and the activity at the end of that period. (Enter your answer for the number of half-lives to at least one decimal place.)  ____half-lives and ____mCi

Find the activity A of a sample containing 4E-6 g of 60/27 Co (T1/2= 5.27 years). (Use 59.93 u as the mass of 60/27 Co.)  Radioactive decay constant: A)2.41E8 B)0.132 C)4.15E-9 D)7.60     Activity in curies: A)4.51E-3 Ci B)8.26E9 Ci C)1.43E8 Ci D)4.51 Ci

an element with initial mass 1 kg started radioactivity in 2021 , in which year the element will lose 0.5 kg ? knowing that the decay constant for element is 693.147*10^-5 / year

Asap plz

The half life for the radioactive decay of Ce-141 is 32.5 days. If the sample has an activity of 4.0 úCi after 130 days have elapsed, what was the initial activity, in microcuries, of the sample?

iodine 131 has a half life of 8.04 days if you start with a radioactivr I 131 sample having an activity equal to 40 microci after how long is the activity going to be 4cmicroci

Question 4. A syuthetic radioisotope is freshly prepared in a lab that has an ac- tivity of 10.0 mCi. If the activity of the radioisotope changes to 8.00 mCi, in 5.00 h, (a) What is the decay constant and half-life of the radioisotope in seconds? (b) How many atoms of the radioisotope were contained in the freshly prepared sam- ple? (e) What is the sample's activity in mCi 40.0 h after it is prepared?