Physics 30: Chapter 8 Exam Nuclear

Transcription

1 Physics 30: Chapter 8 Exam Nuclear Name: Date: Mark: /34 Numeric Response. Place your answers to the numeric response questions, with units, in the blanks at the side of the page. (1 mark each) 1. A 100 g sample of thorium-234 has a half-life of 24.1 days. Determine the remaining amount after 300 days mg 2. Determine the mass-energy equivalence of an electron at rest in units of joules x J 3. A radioactive substance registers 1800 counts per minute on a Geiger counter. 6.0 hours later it registers 450 counts per minute. Determine the half-life of this substance. 3.0 h 4. Determine the electrostatic force between two down quarks inside a proton when separated by a distance of 1.30 x m x N Kennedy

2 Written Response. Show all your work. Clearly identify your final answer(s) rounded off to the proper number of significant digits. 1. An unknown substance undergoes radioactive decay. The following data is collected. Activity Time (d) Activity (Bq) Activity as a function of Time Time (d) a. Plot the data. (2 marks) b. Use the graph to determine the half-life of the substance. (1 mark) c. Identify the unknown substance using the graph and the chart below. (1 mark) d. Write the nuclear decay equation for the substance. (1 mark) Isotope Half-life (d) Decay mode V 16 beta-positive Po 138 alpha Ag 7.5 beta-negative Ir 74 beta-positive Nb 35 beta-negative Kr 1.5 beta-positive The half-life is 27 years, so the substance is most likely Nb which has a half-life of 35 a Nb > 0 β Nb ν Kennedy

3 Multiple Choice. Select the best answer and mark it clearly on your Scantron. (1 mark each) 1. Identify the radiation that is most dangerous to living tissue. a. ultraviolet b. beta c. alpha d. gamma 2. When working around sources of radiation, safety can be increased by a. decreasing exposure time b. increasing shielding c. increasing distance d. all of the above 3. Identify the incorrect notation for an isotope. a Ni b U c Hf d Se 4. Identify the isotope that has 63 protons and 81 neutrons. a. europium-81 b. thallium-81 c. thallium-141 d. europium When a neutron decays it produces a beta-negative particle and a(n) a. proton and neutrino b. proton and antineutrino c. proton and electron d. alpha particle and antineutrino 6. Identify the weakest of the four fundamental forces. a. Gravitational b. Electromagnetic c. Strong Force d. Weak (nuclear) Force 7. Identify the type of nuclear decay that does not result in a transmutation. a. alpha b. beta c. gamma Kennedy

4 8. Identify the transmutation equation for the decay of carbon-14. a B + 0 β ν b B β ν c N β ν d N + 0 β ν 9. An alpha particle that has a kinetic energy of 5.0 MeV collides with a neutron in the beryllium target and transfers 60 % of its kinetic energy to the neutron. Determine the speed of the neutron after the collision. a. 5.7 x 10 8 m/s b. 2.4 x 10 7 m/s c. 2.0 x 10 7 m/s d. 5.7 x 10 7 m/s 10. Identify the process that produces the most energy per gram, from highest to lowest. a. fusion, fission, chemical change b. fusion, chemical change, fission c. chemical change, fusion, fission d. fission, fusion, chemical change 11. A mass of 3.67 x kg is equivalent to an energy of a x J b x J c x J d x 10-8 J 14 7 N + 1 Use the information below to answer question β ν 12. The conservation law that can not be seen to be followed in the above reaction is the law of conservation of a. charge b. Nucleons c. energy d. momentum 13. Cobalt-60 has a half-life of 5.2 years. Determine the amount of cobalt-60 remaining after 3.2 years if the original sample size was 2.0 mg. a mg b mg c. 1.0 mg d. 1.3 mg Kennedy

5 14. Carbon-14 has a half life of 5730 years. Determine the age of a sample having an activity of 17 MBq if its original activity was supposed to be 69 MBq. a a b a c a d a Use the information below to answer questions Traser watches have a lighting system that uses tubes containing tritium (also called hyrdrogen-3) that has a half-life of years. The tritium undergoes beta-negative decay. The emitted beta-negative particles collide with phosphorus based molecules coated on the inside of the glass tubes to produce a green light. 15. The daughter product of the decay of tritium is a. 3 2 H b. 2 1 H c. 4 2 He d. 3 2 He 16. The wavelength of the emitted light is most likely closest to a. 200 nm b. 400 nm c. 500 nm d. 700 nm 17. Determine the percent tritium remaining after 20 years. a. 32 % b. 68 % c. 65 % d. 35 % Kennedy

6 Use the information and diagram below to answer questions When bubble chambers were in common use they allowed for the analysis of many nuclear particles. A photograph was taken showing the tracks of subatomic particles through a bubble chamber inside a magnetic field. Particles enter from here A D C B 18. Particle track A is most likely produced due to a. a high energy photon colliding with an electron b. an electron being created according to E = mc 2 c. scattering of a photon d. the debroglie wavelength of an electron 19. The direction of the magnetic field is a. into the page b. out of the page c. from right to left d. from left to right 20. Identify the track(s) that is/are most likely produced by an electron. a. C and B b. A only c. C d. A and B 21. Identify the track that is most likely produced by a proton. a. A b. B c. C d. D Kennedy

7 22. The Standard Model was originally developed in an attempt to a. account for the dual nature of electrons; waves and particles b. standardize the naming of subatomic particles c. organize the hundreds of different subatomic particles that had been discovered d. organize fractionally charged particles that had been found in the nucleus 23. A proton is composed of a. three antidown quarks b. three down quarks c. one down quark and two up quarks d. two down quarks and one up quark 24. Under the Standard Model, identify the particle that is considered to be an elementary particle. a. proton b. electron c. neutron d. alpha particle 25. Identify the particle from the list below that contains quarks. a. positron b. neutron c. electron d. neutrino Kennedy

8 MC average: Question Answer % Correct Question Answer % Correct 1 D 14 A 2 D 15 D 3 B 16 C 4 D 17 A 5 B 18 A 6 A 19 A 7 C 20 D 8 C 21 D 9 B 22 C 10 A 23 C 11 D 24 B 12 B 25 B 13 D Kennedy