A radioactive element has a half life of 25 hours. After what time will 1/8 of initial number of its atom disintegrate? After what time will 1/32 of the initial number remain unchanged?
Q: A half life is defined as the amount of time taken for the number of radioactive nuclei present in a…
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Q: A piece of bark is made up of carbon. It emits 7000 electrons per minute. Only the carbon 14 isotope…
A: number of electrons per minute = 7000 isotopic abundace of C-14 = 1.3×10-12
Q: ults vary with the amount of the sample. The decay constant represents a percentage of the sample…
A: Decay constant, proportionality between the size of a population of radioactive atoms and the rate…
Q: The number of radioactive atoms in a sample decay as the emission of radiation proceeds and this may…
A: According to the data given Half life is 3hr And relationship given is . N(t) = N0 e(-t/£)
Q: 6. The bismuth-209 nucleus has a binding energy per nucleon of 7.6154 MeV. (1 MeV is 1.60 × 10-13…
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Q: if you started with a parent isotope with 100% of its atoms and its half-life is 10 years. What is…
A: Given. t/T = 2 N(t) = No(1/2)t/T
Q: A geologist finds an old rock and wants to determine its age using rubidium-strontium dating. This…
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Q: The nucleus (15 8) O has a half-life of 122.2 s; (19 8) O has a half-life of 26.9 s. Assume that at…
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Q: The radioactive isotope (95Nb) has a half-life of 35 days. A sample containing this isotope has an…
A: Half life , T12 = 35 days =35 x 24 = 840 hours Initial Activity , A0 = 4.5 x 108 Bq T1 = 36 hours…
Q: A sample of radium Ra (atomic mass=224.020 186 u, T12-3.66 days) contains No-3.68 x 1021 nuclei and…
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Q: radioactive sample initially undergoes 12.0×10^4 decays/s. Twenty-four hours later, its activity is…
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Q: An 10 g sample of a radioactive element takes 5432.6 years to reduce into 1 g. Calculate the…
A: Radioactive decay takes place when an unstable nucleus becomes stable. The instability arises due to…
Q: The isotope 208Tl undergoes β decay with a half-life of 3.1 min. How many minutes will it take for…
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Q: Some nucleus of ¹9X (atomic mass = 189.96182 u) undergoes - decay to become ¹2X1 (atomic mass =…
A: The mass of the parent nucleus is 189.96182 u. The mass of the daughter nucleus is 189.95844 u.…
Q: Carbon is one of the fundamental elements in everything that's alive on Earth. The three naturally…
A: Carbon has generally three isotopes found in nature. Isotopes are those which have the same proton…
Q: The decay of radioactive substance is given by N = Noe (1), where N is the number of atoms present…
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Q: How much energy in kJ is released to form one mole of 75As from protons, electrons, and neutrons if…
A: The sum of the masses of the nucleons is greater than the mass of the nucleus. This difference in…
Q: 10. The radioactive isotope (82Sr) has a half-life of 25.4 days. A sample containing this isotope…
A: Given, The half-life of radioactive elements is 25.4 days The initial activity, R=4.50×108 Bq
Q: Tritium has a half - life of 12.33 years. What fraction of the nuclei in a tritium sample will…
A: Formula to calculate the fraction of remaining sample after 5.00 yr. is,
Q: An unknown isotope has an atomic number, Z = 15 and atomic mass number, A = 32. It decays via beta…
A: Given: The atomic number of an isotope is Z=15. The atomic mass number of an isotope is A=32. The…
Q: A nucleus of copper has an atomic mass of 64.93 u (with Z=29 and A=65). Considering that the mass…
A: Total binding energy of the nucleus is 552.89 Mev
Q: A 5 g sample of a radioactive element takes 102 days to reduce into 3 g. Calculate the half-life and…
A: Radioactive decay takes place when an unstable nucleus becomes stable. The instability arises due to…
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: All the very heavy atoms found in the earth were created long ago by nuclear fusion reactions in a…
A: Given values: Half life of U235, t12(U235)=7.04×108 yr Half life of U238, t12(U238)=4.47×109 yr…
Q: What is the binding energy per nucleon for ?? 13 27 (Aluminum – 27)? Note: A neutral ?? 13 27…
A: The binding energy of a nucleus is the energy required to completely disassemble the nucleus into…
Q: The barium isotope 131 Ba has a half-life of 12 days. A 300 µg sample of 131 Ba is prepared.
A: Write the given values of this problem. Half-lifeT12=12 dayst=1 daysample(No)=300 μg
Q: The radioactive isotope of lead ^209Pb decays according to the differential equation dN/dt=-kN. The…
A: Remaining fraction = (100-78)/100 e^-(.693t/3.3) = .22 take ln both sides - .693t/3.3 = ln (.22) =…
Q: Radioactive potassium-40 has a half-life of 4.2 x 1016 s. a) Calculate the decay constant of…
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Q: What fraction f1 of a radioactive sample will be left after 3 half‑lives? f1 = ? What fraction f2…
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- Identify the isotope notation for the isotope of cadmium that has 54 neutronsAt t = 0 we begin to observe two identical radioactive nuclei that have a half-life of 5 min. At t = 1 min, one of the nuclei decays. Does that event increase or decrease the chance that the second nucleus will decay in the next 4 min, or is there no effect on the second nucleus? (Are the events cause and effect, or random?)Q3: The table shows two isotopes of potassium and two isotopes of calcium. Type of emission Mass of neutral atom / u Number of electrons Number of protons Number of neutrons Total mass/u Mass defect/ u Binding energy / J Mass of the electron = 0.000549 u Mass of the proton = 1.007276 u Mass of the neutron = 1.008665 u TI ***** LEG 39K Stable 38.96371 SE nda 42K ß decay a) Use data about potassium-42 to explain the concept of mass defect. 3000 41.9624 19 19 23 42.34797 0.38557 5.76 x 10-11 De RAP 39 Ca ßt decay 38.9707 440 **** ****** D 42 Ca stable 41.95863
- 4. I have two isotopes A and A' of an element with half-lives T/2 and Ti2 respectively. (a) Show that with time, the amount of A' relative to A is NA (t) f (t) = NA (t) = f (0) exp In (2) ( (b) The half-lives of 238U and 235U are 4.5 billion years and 700 million years, respectively. Natural uranium is currently about 97.3% 238U and 0.7% 235U. Based on the formula in (a), how long ago would you have been able to build an atomic bomb out of natural uranium ore, given that "weapons grade" uranium is at least 80% 235U? [MY]An unknown element X has the following isotopes: ⁶⁴X (49.00% abundant), ⁶⁶X (28.00% abundant), ⁶⁸X (23.00% abundant). What is the average atomic mass in amu of X?Time 0 t₁2 20₁2 3₁/12 Number of nuclides, N x 10³ 1000 750 500 90/2 10/₁2 250 125 0 12 212 312 412 512 612 7h2 8h2 9h12 10/2 Time in multiples of t₁/2 The figure shows a typical radioactive decay (amount of undecayed nucleus (N) vs. time (t)) from a heavy nucleus. Such a decay may be best expressed by an equation like : ON = N₂ (xt) ON=N₂/λt -λt ON = N₂e N = N₂ e-1/At N 1,000,000 500,000 250,000 125,000 62,500 31,250 15,625 7,813 3,906 1,953 977 412 5/₁/2 61₁2 7h2 81/2
- You inherit 32 kg of cesium-136 after your roommate moves out and leaves it behind. Cesium-137 has a half-life of 30 years. If you pack it in a box and forget about it, but your grandchildren finds it in the attic 90 years from now, how much of the sample is still cesium-137?Radon gas has a half-life of 3.83 days. If 2.70 g of radon gas is present at time t = 0, what mass of radon will remain after 2.40 days have passed?A radioactive nucleus has half-life T1/2. A sample containing these nuclei has initial activity R0. Calculate the number of nuclei that decay during the interval between the times t1 and t2.