Physics 3204 UNIT 3 Test Matter Energy Interface

Size: px

Start display at page:

Download "Physics 3204 UNIT 3 Test Matter Energy Interface"

Dwain Brooks
5 years ago
Views:

1 Physics 3204 UNIT 3 Test Matter Energy Interface Time: 60 minutes Total Value: 33 Marks Formulae and Constants v = f λ E = hf h f = E k + W 0 E = m c 2 p = h λ 1 A= A T 0 2 t 1 2 E k = ½ mv 2 r n = 5.29 x m (n 2 ) E n =!13.6 ev /n 2 mass e- = 9.11 x kg = u mass p+ = 1.67 x kg = u mass n = 1.67 x kg = u 1u = x kg = MeV/c 2 c = x 10 8 m/s 1eV = x J h = x J.s e- =!1.602 x C Section A Instructions: DO NOT PLACE YOUR ANSWERS ON THIS SHEET. Instead use the answer sheet to be found on page 5 of this test. For questions 1 28 put the appropriate letter in the blanks on the answer sheet. 1. If the stopping potential of a photoelectric cell is 5.60 V, what is the maximum kinetic energy of the photoelectrons emitted? J J J J 2. What happens to the debroglie wavelength of an electron if its momentum is doubled? decreases by a factor of 2 decreases by a factor of 4 increases by a factor of 2 increases by a factor of 4 3. If an electron orbiting an atomic nucleus moves to a lower energy level, which of the following describes what will happen to the energy of the atom? cannot be determined decreases increases remains the same Physics 3204 Unit 3 Exam June 2006 Page 1 of 7

2 4. For a hydrogen atom, what is the difference in radii between the sixth Bohr orbital and the second Bohr orbital? 1.32 x m 1.17 x m 8.46 x m 1.69 x 10 9 m 5. The Compton Effect describes which of the following phenomena? photon absorption photon emission photon scattering photon transfer 6. A blackbody is an ideal system that absorbs 50% of the light incident upon it, and emits 50% of the radiation it generates absorbs 100% of the light incident upon it, but cannot emit light of its own either absorbs 100% of the light incident upon it, or emits 100% of the radiation it generates emits 100% of the light it generates, but cannot absorb radiation on its own 7. What is the photon momentum of a photon of radiation with a wavelength of 100 nm? 6.63 x kg.m/s 6.63 x kg.m/s 2.0 x kg.m/s 2.21 x kg.m/s 8. Which of the following forms of electromagnetic radiation has photons of the highest energy? gamma radiation infrared radiation radio waves ultraviolet light 9. Polonium has more isotopes that any other element, and they are all radioactrive. Which of these describes the contents of the nucleus of the Po isotope? 218 protons and 84 neutrons 84 protons and 218 neutrons 134 protons and 84 neutrons 84 protons and 134 neutrons 10. Radioactive material emits three types of radiation: alpha, beta and gamma. In the proper order, rays 1, 2 and 3 represent alpha, beta gamma alpha, gamma, beta beta, alpha, gamma beta, gamma, alpha Po decays by alpha decay. Which of the following is the resulting isotope? Physics 3204 Unit 3 Exam June 2006 Page 2 of 7

3 206 Pb 208 Bi Bi 210 Pb What does the X represent in the following equation? Bi Pb+ X β+ particle β- particle helium nuclei antineutrino 13. When 7 3Li undergoes beta- decay, it transmutes to 3 H 3 He He 7 Be What is the mass of a positron? zero 9.11 x kg 1.67 x kg 6.65 x kg 15. In electron capture one of the protons decays into a neutron the excited daughter emits beta + particles the parent and daughter elements have the same atomic mass and atomic mass numbers the parent nucleus emits gamma radiation 16. Scientists were led to predict the existence of the neutrino in order to Maintain the conservation of energy in beta decay explain the intense radiation emitted by positrons account for alpha decay provide a mechanism for nucleon production 17. What is the half-life of an isotope, if 87.5 % of a sample decays in 24 days? 6 days 8 days 12 days 14 days 18. Americium-243 has a half-life of approximately 7000 years. If a smoke detector containing 20 mg of this isotope were discarded and then rediscovered 70 years later, approximately how much americium- 243 would remain? 20 mg 0.20 mg 2.0 x 10-7 mg No measurable amount would remain Physics 3204 Unit 3 Exam June 2006 Page 3 of 7

4 19. In a nuclear reactor control rods made of cadmium metal can be inserted or withdrawn from the reactor. What is the purpose of the control rods? absorb neutrons release neutrons slow down the neutrons speed up the neutrons 20. Which of the following is used as a moderator in a CANDU reactor? graphite heavy water hydrogen uranium Physics 3204 Unit 3 Exam June 2006 Page 4 of 7

5 Name: School: Answer Sheet for Section A Print Your Choice Clearly Section B: Problems. Answer all questions, showing all workings. {4} 21. Light with a wavelength of 425 nm falls on a photoelectric surface that has a work function of 2.00 ev. What is the maximum speed of the ejected electron? Physics 3204 Unit 3 Exam June 2006 Page 5 of 7

6 {2} 22. a) An electron in a hydrogen atom drops from the third energy level to the second energy level. Calculate the energy emitted. {2} b) Given that the visible spectrum falls between 450 nm and 750 nm, determine if the energy emitted in part a) falls in the visible spectrum. Physics 3204 Unit 3 Exam June 2006 Page 6 of 7

7 Name: School: {3} 23. Uranium-239 undergoes a series of radioactive decays to become Uranium-238. Each step in the progression represents a different decay. Fill in the blanks to complete the following progression from Uranium-239 to Uranium-235. E quation Decay Type U 93 Np Np 94 Pu Pu 92 U + {4} 24. Given the masses below, calculate the energy released when a U nucleus is fissioned. 235 U = x kg 142 La = x kg 91 Br = x kg n = x kg U n La Br n Physics 3204 Unit 3 Exam June 2006 Page 7 of 7

SECTION A Quantum Physics and Atom Models

AP Physics Multiple Choice Practice Modern Physics SECTION A Quantum Physics and Atom Models 1. Light of a single frequency falls on a photoelectric material but no electrons are emitted. Electrons may