A radioactive sample with a half-life of 5.3 weeks has 1.04e+15 nuclides present in the initial sample. a) What is the initial activity of this sample? Bq b) How many days does it take for this sample to decay to 3.09e+14 nuclides? days

Question 2. A piece of charcoal used for cooking is found at the remains of an ancient campsite. A 1.00 kg sample of carbon from the wood has an activity equal to 5.00 x 10* decays per minute. Find the age of the charcoal. Hint: Living material has an activity equal to 15.0 decays/min per gram of carbon present.

The half-life of Ra-226 is 1.60 x 10^3 years = 5.05 x 10^10 s Find k What is the activity in curies of a 1.00 g sample? What is the mass in grams of a Ra-226 sample that has an activity of 1.00 x 10^9 atoms/min?

Chromium's radioactive isotope 51Cr has a half-life of 27.7 days and is often used in nuclear medicine as a diagnostic tracer in blood studies. Suppose a 51Cr sample has an activity of 2.36 µCi when it is placed on a storage shelf.   (a) How many 51Cr nuclei does the sample contain?  Answer:__________ nuclei   (b) Calculate the sample's activity in Bq when it is removed from storage one year later.  Answer:____________Bq

There is more than one isotope of natural uranium. If a researcher isolates 0.7 mg of the relatively scarce 235U and finds this mass to have an activity of 78.0 Bq, what is its half-life in years? =___years

The decay chain of uranium includes radon, a noble gas. When uranium in the soil decays to radon, it may seep into houses; this can be a significant source of radiation exposure. Most of the exposure comes from the decay products of radon, but some comes from alpha decay of the radon itself. If radon in the air in your home is at the maximum permissible level, the gas in your lungs will have an activity of about 0.22 Bq. Each decay generates an alpha particle with 5.5 MeV of energy, and essentially all that energy is deposited in lung tissue. Part A Over the course of 1 year, what will be the dose equivalent in Sv to the approximately 0.90 kg mass of your lungs? Express your answer in millisieverts per year. ΕΧΕΙ ΑΣΦ dose equivalent = ? mSv/yr

11. Radium-226, 226Ra, undergoes an alpha decay. The current sample of Radium-226 has an initial activity of 5.50 × 101º Bq. (a) Identify the daughter nucleus by name, nucleon number, atomic number and neutron number. (b) What is the decay constant? (c) How many radioactive nuclei were initially present in the sample? (d) How long will it take the sample to reach an activity of 5.00 x 1010 Bq?

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The amount of radioactive 40K in a 70kg person is approximately 5000Bq. A) what is the number (N) of radioactive 40K nuclei in the body? The half life of 40K is 1.25x109 years. B)What is the amount of natural potassium (in grams) in the body? The abundance of 40K is 0.012% of the natural potassium 39K