A radioactive sample has a mass of 185 grams. How much remains after 2 half lives?

Q: A radioactive material produces 3.522E+3 decays per minute at one time, and 5.47 h later produces…

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Q: A radioactive sample has a decay constant of 55.0 x 10-¹2 s¹. Estimate its half-life.

A: Radioactive decay is the process by which unstable nuclei spontaneously lose energy to become…

Q: A 30 g radioactive isotope has a half-life of 6 years. How much of the isotope will be left after 12…

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Q: a) Natural potassium contains 40K , which has a half-life of 1.277×109 years. What mass of 40K in a…

A: a) The number of radioactive nuclei is,

Q: After how many half-lives will (a) 10.0%, (b) 5.00%, and (c) 1.00% of a radioactive sample remain?

A: Formula to calculate the number of half-lives is,

Q: Atts, you have a pure sample of an unknown substance. At t= 293 s, 36.8% of the substance remains.…

A: Radioactive substance remaining at t=293s, N=36.8100×N0=0.368N0

Q: If a material has a half life of 92.5 days, how long will it take for 75% of the material to decay?…

A: Half life of the material=92.5days 75% of the material decay

Q: Krypton-81m (81mKr) is a radioactive isotope with a half-life of 13.1 s that is often used in…

A: The correct option is (e) 50.26 s

Q: How many half-lives would have to elapse for a sample of a radioactive isotope to decrease from an…

A: No = 192 cpmN = 3 cpm

Q: How many half-lives would it take for 6.02×10 ^23 nuclei to decay to 6.25%(0.376×10^23) of the…

A: Initial no. Of nuclei( No)  =6.02×1023 Final no. Of nuclei(N)=0.376×1023 ;(6.25% of initial no. Of…

Q: The half life for the decay of carbon-14 is 5.73*10^3 years. Suppose the activity due to the…

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Q: What is the mass of 1ci of 227TH? If the half-life is 1.90 years. O m = 1.11x 10-2g O m = 1.21x…

A: T1/2 = 1620 years = 1620 x 3.15 x 107s λ = 0.693/ T1/2 = 0.693/(1620 x 3.15 x 107 s)

Q: If a 3.16-g sample of an isotope having a mass number of 135 decays at a rate of 0.530 Ci, what is…

A: Given Mass of Isotope = 3.16 gram = 3.16×10-3 Kg Mass Number = 135  Rate of decay = 0.530 Ci As…

Q: the decay constant or the beta decay of ^99 43Tc was found to be equal to 1.0x10-13/s. What is the…

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Q: sample of radioactive material starts with 0 grams. After 3 half lives have passed, how much…

A: Half-life is the amount of time it takes for one half of a sample of a radioactive isotope to decay.…

Q: A radioactive sample has a mass of 999 grams. How much remains after 2 half-lives?

A: If the amount of a radioactive sample is N0 initially, then after 1st half live of the sample, it…

Q: Radon-222 has a half-life of 3.8 days. What mass of radon-222 would have a decay rate of 2220 Bq?…

A: We use the formula of rate of decay to get the required values.

Q: The decay constant of a radioactive source is 752 per year. Then its half- life equals: *

A: Step:1   The  Time  taken  for a radioactive atom    to  disintegrate  to half  of its  original…

Q: What is the mass of 1ci of 227Th? If the half-life is 1.90 years.

A: T1/2 = 1.90 years        = 1.90 x 3.15 x 107 s λ = 0.693/T1/2    = 0.693/(1.90 x 3.15 x107s)

Q: A radioactive sample has a decay constant of 2.97 x 10 s¹¹. Estimate the half-life.

A: Unstable nuclei decay into a stable state. This process is called radioactivity. The rate at which…

Q: Sihle, an archaeologist from UWC finds an ancient wooden axe handle at an excavation site at…

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Q: A radioactive sample contains 2048 nuclie. How many of its nuclei decay after two half lives?

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Q: A tree falls in a forest. How many years must pass before the C activity in 1.00 g of the tree's…

A: mass = 1 g number of atoms = number of moles * avogadro number  = (1/14)(6.022 * 1023) = 4.3 * 1022…

Q: The Half-life of certain radioactive sample is 30 minutes. At 2.00 PM, the decay rate is measured to…

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Q: A nuclide whose "generic" symbol is 6430X would have protons and neutrons.

A: The generic symbol of a nuclide is given as X3064.

Q: What is the Decay Rate (k), if the Half Life is 10.5 days?

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Q: What percentage of a radioactive substance remains after  7.00 half-lives have elapsed?

A: Time=7 half life

Q: Radioactive decay of unstable atomic nuclei is a first order process. The half life for the…

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Q: Natural Uranium, as found on earth, consists of two isotopes in the ratio of ^ 235 U/ ^ 238 U=0.07…

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Q: A radioactive material produces 4.386E+3 decays per minute at one time, and 7.57 h later produces…

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Q: How many half lives must pass for the mass of a radioactive sample to decrease to 35% of the…

A: Half life of a radioactive sample is the time required for the sample to reduce to half of its…

Q: Supposed that a radioactive substance has decayed until only of 1/8 of it remains. How many…

A: let initial number of Nucleons= N0 remaining number of Nucleons= N =N08

Q: Tritium (half-life = 12.3 yr) is used to verify the age of expensive brandies. If an old brandy…

A: The amount remaining is equal to the original amount times 1/2 raised to the of half-lives that have…

Q: The half-life for the a decay of uranium 2U is 4.47 x 10° yr. Determine the age (in years) of a rock…

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Q: After 85 years, 80 % of a radioactive material decays. What is the half-life?

A: Given, Time,t=85yrs=85×3.154×107sPercentage of the material decay= 80% We have the expression for…