1 / 59

13 x 10 7 7 x 10 8 3 x 10 10 8 x 10 12

Approximately how many radioactive atoms are present in a tritium sample with an activity of 0.4 x 10 -6 Ci and a half-life of 12.3 years? (1 Ci = 3.7 x 10 10 decays/s). 13 x 10 7 7 x 10 8 3 x 10 10 8 x 10 12.

oakes
Download Presentation

13 x 10 7 7 x 10 8 3 x 10 10 8 x 10 12

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Approximately how many radioactive atoms are present in a tritium sample with an activity of 0.4 x 10-6 Ci and a half-life of 12.3 years? (1 Ci = 3.7 x 1010 decays/s) • 13 x 107 • 7 x 108 • 3 x 1010 • 8 x 1012

  2. What is the binding energy per nucleon of Au-197 (atomic number = 79)? (The following information regarding atomic masses will be needed: Au-197, 196.966560; hydrogen, 1.007825; neutron, 1.008665; also 1 u x c2 = 931.5 MeV) • 7.3 MeV • 7.7 MeV • 7.9 MeV • 8.3 MeV

  3. Approximately how many half-life periods must elapse if the activity of a radioactive isotope sample is to be reduced to 0.004 of the original value? • 3 • 6 • 8 • 60

  4. Tritium has a half-life of 12.3 years. What proportion of its original radioactivity will a sample have after 9 years? • 0.55 • 0.60 • 0.73 • 0.84

  5. The activity of a newly discovered radioactive isotope reduces to 96% of its original value in an interval of 2 hours. What is its half-life? • 10.2 hrs • 34.0 hrs • 44.0 hrs • 68.6 hrs

  6. If there are 128 neutrons in Pb-210, how many neutrons are found in the nucleus of Pb-206? • 122 • 124 • 126 • 130

  7. The existence of the neutrino was postulated to account for which basic conservation laws during the beta decay process? • conservation of energy • conservation of momentum • both of the choices are valid • none of the choices are valid

  8. A radioactive isotope which emits a gamma quantum will change in what respect? • atomic number increases by one • atomic number decreases by one • atomic mass number decreases by one • none of the choices are valid

  9. A radioactive isotope which emits an alpha particle will change in what respect? • atomic number decreases by four • mass number decreases by four • both atomic number and mass number decrease by four • none of the choices are valid

  10. Tritium has a half-life of 12.3 years. How many years will elapse when the radioactivity of a tritium sample diminishes to 10% of its original value? • 31 years • 41 years • 84 years • 123 years

  11. A pure sample of Ra-226 contains 2.0 x 1014 atoms of the isotope. If the half-life of Ra-226 = 1.6 x 103 years, what is the decay rate of this sample? (1 Ci = 3.7 x 1010 decays/s) • 2.7 x 10-12 Ci • 3.4 x 10-10 Ci • 7.5 x 10-8 Ci • 9.6 x 10-6 Ci

  12. What energy must be added or given off in a reaction where one hydrogen atom and two neutrons are combined to form a tritium atom? (atomic masses for each: hydrogen, 1.007825; neutron, 1.009665; tritium, 3.016049; also, 1 u x c2 = 931.5 MeV) • 8.5 MeV added • 8.5 MeV given off • 10.3 MeV given off • 10.3 MeV added

  13. An ancient building was known to have been built 3000 years ago. Approximately what proportion of C-14 atoms are yet in the building's wooden framing compared to the number which were present at the time of its construction? (half life of C-14 = 5800 years) • 0.425 • 0.500 • 0.517 • 0.698

  14. The isotope Zn-64 has a nuclear radius of 4.8 x 10-15 m. Which of the following is the mass number of an isotope for which the nuclear radius is 7.2 x 10-15 m? • 144 • 96 • 125 • 216

  15. A pure sample of Ra-226 contains 2 x 1014 atoms of the isotope. If the half-life of Ra-226 = 1.6 x 103 years, what is the decay rate of this sample? • 6.7 x 109 decays/yr • 8.7 x 1010 decays/yr • 9.4 x 1010 decays/yr • 12.6 x 10-10 decays/yr

  16. The beta emission process results in the daughter nucleus differing in what manner from the parent? • atomic mass increases by one • atomic number decreases by two • atomic number increases by one • atomic mass decreases by two

  17. The gamma radiation first detected by Becquerel was in fact which of the following? • helium nuclei • high energy quanta • electrons • positrons

  18. The alpha emission process results in the daughter nucleus differing in what manner from the parent? • atomic mass increases by one • atomic number decreases by two • atomic number increases by one • atomic mass decreases by two

  19. If the sum total mass of reactants in a nuclear reaction is greater than that of product particles, then which of the following statements best describes the conditions of the reaction? • reaction is exothermic • reaction is endothermic • atomic number of each reactant must be greater than 40 • atomic number of each reactant must be less than 80

  20. The isotope Zn-64 has a nuclear radius of 4.8 x 10-15 m. Approximately what is the nuclear radius of an isotope of Al-27? • 2.0 x 10-15 m • 2.7 x 10-15 m • 3.6 x 10-15 m • 4.0 x 10-15 m

  21. The ratio of the numbers of neutrons to protons in the nucleus of naturally occurring isotopes tends to vary with atomic number in what manner? • increases with greater atomic number • decreases with greater atomic number • is maximum for atomic number = 60 • remains constant for entire range of atomic numbers

  22. The atomic mass number of a nucleus is equivalent to which of the following numbers? • # neutrons present • # protons present • difference in neutron and proton numbers • sum of neutron and proton numbers

  23. Of the main types of radiation emitted from naturally radioactive isotopes, which of the following is the most penetrating? • alpha • beta • gamma • positron

  24. Samples of two different isotopes, X and Y, both contain the same number of radioactive atoms. Sample X has a half life twice that of Y. How do their rates of radiation compare? • X has a greater rate than Y • X has a smaller rate than Y • rates of X and Y are equal • rate depends on atomic number, not half life

  25. The beta radiation first detected by Becquerel was in fact which of the following? • helium nuclei • high energy quanta • electrons • positrons

  26. The alpha radiation first detected by Becquerel was in fact which of the following? • helium nuclei • high energy quanta • electrons • positrons

  27. The atomic number of a given element is equivalent to which of the following? • proton number in the nucleus • neutron number in the nucleus • sum of the protons and neutrons in the nucleus • number of electrons in the outer shells

  28. Chromium-55 (54.9279 u) emits an electron (0.0005 u) leaving a daughter nucleus of manganese-55 (54.9244 u). How much energy is released in this reaction? (1 u x c2 = 931 MeV) • 5.59 MeV • 2.79 MeV • 1.40 MeV • 0.70 MeV

  29. An endothermic nuclear reaction occurs as a result of the collision of two reactant nuclei. If the Q value of this reaction is -2.17 MeV, which of the following describes the minimum kinetic energy needed in the reactant nuclei if the reaction is to occur? • equal to 2.17 MeV • greater than 2.17 MeV • less than 2.17 MeV • exactly half of 2.17 MeV

  30. If a fossil bone is found to contain 1/8th as much Carbon-14 as the bone of a living animal, what is the approximate age of the fossil? (half-life of C-14 = 5800 years) • 8,000 years • 17,400 years • 23,000 years • 46,400 years

  31. Rutherford's experiments involving the use of alpha particle beams directed onto thin metal foils demonstrated the existence of which of the following? • neutron • proton • nucleus • positron

  32. The components of natural radiation, in order of least to most penetrating, are which of the following choices? • alpha, beta and gamma • gamma, beta and alpha • beta, gamma and alpha • alpha, gamma and beta

  33. A radioactive material initially is observed to have an activity of 800 counts/sec. If four hours later it is observed to have an activity of 200 counts/sec, what is its half life? • 1 hour • 2 hours • 4 hours • 8 hours

  34. The experiment which gave the first evidence for the existence of the atomic nucleus involved which of the following? • X-ray scattering • radioactive dating • cosmic ray detection • alpha scattering

  35. The nucleus of an atom is made up of which of the following? • electrons and protons • electrons and neutrons • protons, electrons and neutrons • protons and neutrons

  36. Radium-226 decays to Radon-222 by emitting which of the following? • beta • alpha • gamma • positron

  37. When bismuth-214 emits a beta particle, the remaining daughter nucleus is which of the following? • lead-213 • actinium-215 • polonium-214 • bismuth-215

  38. Certain stars at the end of their lives are thought to collapse combining their protons and electrons together to form a neutron star. Such a star could be thought of as a giant atomic nucleus. If a star of mass equal to that of the sun (M = 2 x 1030 kg) collapsed into neutrons (mn = 1.67 x 10-27 kg), what would be the radius of such a star? (HINT: r = r0A1/3) • 25.4 km • 18.7 km • 12.7 km • 6.4 km

  39. Calculate the binding energy of the tritium nucleus, given that the mass of the tritium nucleus is 3.01605 u. (mp = 1.007276 u, mn = 1.008665, and 1 u = 931.5 MeV/c2) • 2.24 MeV/nucleon • 2.45 MeV/nucleon • 2.66 MeV/nucleon • 2.86 MeV/nucleon

  40. The half-life of radioactive iodine-131 is 8 days. Find the number of 131I nuclei necessary to produce a sample of activity 1.0µ Ci. (1 Curie = 3.7 x 1010 decays/second) • 4.6 x 109 • 3.7 x 1010 • 7.6 x 1012 • 8.1 x 1013

  41. How much kinetic energy must an alpha particle (charge = 2 x 1.6 x 10-19 C) have to approach to within 10-14 m of a gold nucleus (charge = 79 x 1.6 x 10-19 C)? [k = 9 x 109 N-m2 /C2 and 1 MeV = 1.6 x 10-13 J] • 11.70 MeV • 14.55 MeV • 18.15 MeV • 22.75 MeV

  42. Tritium is radioactive with a half-life of 12.33 years decaying into with low-energy electron emission. If we have a sample of 3 x 1018 tritium atoms, what is its activity in decays/second? (1 year = 3.15 x 107 s) • 4.20 x 1010/second • 5.35 x 109/second • 3.69 x 108/second • 6.64 x 107/second

  43. An alpha particle (mass = 6.68 x 10-27 kg) is emitted from a radioactive nucleus with an energy of 5 MeV. How fast is the a-particle moving in m/s? (1 MeV = 1.6 x 10-13 J) • 2.40 x 107 m/s • 1.55 x 107 m/s • 3.70 x 106 m/s • 1.85 x 106 m/s

  44. A 1-gram sample of petrified wood is taken from a petrified forest. If the Carbon-14 activity of the sample is 12.5% that of present-day organic material, what is the age of the petrified wood? (T1/2 for C-14 is 5,730 years) • 4,460 years • 8,600 years • 13,150 years • 17,200 years

  45. In the beta decay of 14C, the existence of the anti-neutrino was required to maintain? • energy conservation. • charge conservation. • conservation of the number of nucleons. • all of the choices

  46. The fact that the binding energy per nucleon doesn't depend very strongly on the volume of the nucleus indicates that? • the strong nuclear force saturates. • nucleons don't move throughout the nucleus. • all nuclei have the same volume. • the radius of a nucleus is directly proportional to the number of nucleons.

  47. According to the shell model of the nucleus, radioactive decay which produces beta rays occurs because? • there is a vacant energy level for a neutron and as a neutron drops down to this lower energy level it gives up its energy to an electron. • there is no vacancy in a neutron energy level so the neutron goes to an energy level previously occupied by an electron. • the neutron must change to a proton before it can go to a lower energy level. • the neutron gets rid of excess angular momentum by giving it to ejected electron.

  48. Some nuclei are not spherical and this can best be explained by the? • liquid drop model. • shell model. • collective model. • model of nuclear tunneling.

  49. If the stable nuclei are plotted with neutron number vs. proton number, the curve formed by the stable nuclei does not follow the line N = Z. This is predicted by examining how the binding energy is influenced by? • the volume of the nucleus. • the size of the nuclear surface. • the Coulomb repulsion. • the proton-neutron mass difference.

  50. The binding energy of a nucleus is equal to? • the energy needed to remove one of the nucleons. • the average energy with which any nucleon is bound in the nucleus. • the energy needed to separate all the nucleons from each other. • the mass of the nucleus times c2.

More Related