Atomic Physics Section Quiz: Quantization of Energy
Transcription
Atomic Physics Section Quiz: Quantization of Energy
Name Class Date Assessment Atomic Physics Section Quiz: Quantization of Energy Write the letter of the correct answer in the space provided. ______ 1. Which of the following phrases correctly describes a blackbody? a. object from which neither light nor matter escapes b. absorbs all radiation and emits no radiation c. emits all radiation and absorbs no radiation d. perfectly absorbs and emits all radiation ______ 2. Classical electromagnetic theory predicted that the energy radiated by a blackbody would become infinite as the wavelength of the radiation became shorter. What was the contradiction between observation and this result called? a. the Compton shift b. the ultraviolet catastrophe c. the photoelectric effect d. the quantum theory ______ 3. Which of the following statements is true about the energy of a quantum of radiation? a. Energy increases with wavelength. b. Energy increases with frequency. c. Energy increases with intensity. d. Energy increases with speed. ______ 4. What is the energy of a photon with a frequency of 5.45 1014 Hz? (h 6.63 1034 J•s) a. 3.61 1019 J b. 3.61 1034 J c. 3.65 1040 J d. 1.22 1048 J ______ 5. What is the frequency of a photon with an energy of 1.3 1019 J? (h = 6.63 1034 J•s) a. 8.6 1020 Hz b. 1.5 106 Hz c. 2.0 1014 Hz d. 1.2 1052 Hz Copyright © by Holt, Rinehart and Winston. All rights reserved. Holt Physics 137 Quiz Name Class Date Atomic Physics continued ______ 6. For a photoelectron to be emitted by a metal that is exposed to photons, the energy of the photons must be greater than what property of the metal? a. its threshold frequency b. its ionization energy c. its electronegativity d. its work function ______ 7. A metal with a work function of 3.5 eV is exposed to photons with an energy of 3.7 eV. What is the maximum kinetic energy of the emitted photoelectrons? a. 7.2 eV b. 3.7 eV c. 3.5 eV d. 0.2 eV ______ 8. Which of the following statements correctly describes the Compton shift that occurs when photons scatter from electrons? a. Electron momentum decreases as electrons scatter from photons. b. Photon wavelengths shorten as they gain energy from electrons. c. Photon wavelengths lengthen as they lose energy to electrons. d. Scattered photons interfere with each other at different angles. 9. Explain why the concept of quanta was required to make theoretical predictions for blackbody radiation match the experimental observations. 10. Photons with a frequency of 6.6 1014 Hz shine on the surface of a metal with a work function of 2.4 eV. What is the maximum kinetic energy of the emitted photoelectrons? (h 6.63 1034 J•s; 1 eV 1.6 1019 J) Copyright © by Holt, Rinehart and Winston. All rights reserved. Holt Physics 138 Quiz TEACHER RESOURCE PAGE 10. Answers may vary. Sample answer: 10. 0.3 eV Microwaves have long wavelengths, low frequency, and relatively low energy. Microwaves are used to cook food, transmit telephone, computer and satellite data, and radar. Given f 6.6 1014 Hz hft 2.4 eV h 6.63 1034 J•s 1 eV 1.6 1019 J Solution KEmax hf hft KEmax (6.63 1034 J•s)(6.6 1014 Hz) 21 Atomic Physics QUANTIZATION OF ENERGY 1. 2. 3. 4. d b b a Given f 5.45 1014 Hz h 6.63 1034 J•s Solution E hf (6.63 1034 J•s)(5.45 1014 Hz) 3.61 1019 J 5. c Given E 1.3 1019 J h 6.63 1034 J•s Solution E 1.3 1019 J f h 6.63 1034 J•s 2.0 1014 Hz 6. d 7. d Given hf 3.7 eV hft 3.5 eV Solution KEmax hf hft 3.7 eV 3.5 eV 0.2 eV 8. c 9. Classical electromagnetic theory predicted that, as the wavelength of light approached zero, the amount of energy emitted by a blackbody would become infinite. By limiting the frequencies that a blackbody could radiate to fixed integral increments, Planck was able to modify the classical theory so that radiated energy reached a maximum at a particular frequency and then decreased toward zero, as was indicated by experimental results. 1eV 2.4 eV 1.60 1019 J KEmax 2.7 eV 2.4 eV 0.3 eV 21 Atomic Physics MODELS OF THE ATOM 1. 2. 3. 4. 9. b 5. c b 6. a d 7. b c 8. c The Rutherford model of the atom had a compact, massive nucleus that contained the positive charge of the atom. The electrons orbited this nucleus in a manner similar to planets orbiting the sun. This model correctly accounted for the nucleus, but according to classical electromagnetic theory, the orbiting electrons would radiate energy continuously, and so could not maintain stable orbits. Also, Rutherford’s model provided no explanation for emission or absorption spectra. 10. In the Bohr model of the atom, electrons move in orbits around the nucleus, much like planets orbit the sun. However, only specific orbits are stable and can thus be occupied by the electrons. When electrons are in these orbits, they do not emit radiation, as predicted by classical electromagnetic theory. Radiation is emitted when electrons move from higher-energy levels to lower-energy levels, which accounts for the individual lines of emission spectra. However, Bohr’s model could not explain why the stable orbits existed, or why radiation was not emitted when the electrons were in these orbits. The Bohr model also did not predict the spectra for atoms with more than one electron in their outermost energy levels. Copyright © by Holt, Rinehart and Winston. All rights reserved. Holt Physics 172 Answer Key
Similar documents
INTERNATIONAL UNIVERSITY OF PSYCHOSOCIOLOGY AND RADIATION SCIENCE, TEL AVIV-YAFO, TEL AVIV, KINGDOM OF JUDAH By Professor (Grandmaster) Adefioye Sunday Adewumi
From basics of radiation to advanced application of radiation science, the International University of Psychosociology and Radiation Science provides a rare, novel and pioneering opportunity in scientific research and development towards sustainable application of the integration of psychosociology and radiation sciences to all facets of human development and in solving key international, regional, national, organizational, local, professional and personal challenges using practical psychosociological and radiation principles. This document and publication officially establish this University.
More information