qz8 - E2= 6.0 eV .................................. c) What...

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Physics 14 - Quiz 8 - Winter 2009 SHOW ALL YOUR WORK AND REASONING 1. (2 pts) A friend gives you a radioactive isotope in a box and asks you to open it in 1 ~ The isotope has a half-life of 4 hours. When you open the box and analyze the sample, there IS just 25 grams of the radioactive isotope left. What was the original mass of the isotope? 1\ "" V j 1 '-/ '" / - ~ . > r~ ::T ~l.l'-I( 1 =' ;~}(I(~f~ Q~fj~ . lIAkl ~ .1~ ~ &-c- tt ~ 2. (1 pt) What really happens when'beta decay occurs? ... 1 f'W\(~~ a-f ~ ~ ~~ VtMctv;S' @ -7> (iJ 1- a t-@ CC~<r ~ ~0 3. (3 pts) The energy levels of an atom are shown below. The ground state of the atom (E1)is shown. An electron is in the second excited state, with energy E3= 10.0 eV. a) How could the electron have gotten to this state? Abs~kd ea. . ~Vw~ E.t=12.0 eV . . t C1 V E3= 10.0 eV en ~ tl)t .O~ ~ COv',.y O'i\ ~\b vl~ A~ ~ i'll(~W~~ ) b) What is the energy oftne-t1ighest frequ~ncy photon that this excited electron can emit?
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Unformatted text preview: E2= 6.0 eV .................................. c) What is the energy of the lowest frequency photon that this excited electron can emit? t """" "-~-t 2:::0 lO-(, =: ~ 4. (2 pts) Why can intense red light not cause electrons to be emitted from a metal surface but weak ultraviolet light can? It t2Q~~'\j ~ ~ ~~ld ~~ atJ M-e ~ ~ ~8/-.-p~h-/ ~~-h> ~Jecl-CL1 p~f-o~ lQ~ '\k ~~fJf/bJ(N}; ~ c~ P~). A~~l.u VlV p~b ~ lol7) tA4J ~ 5. (2 pts) An isoto e of Astatine ( 88sAt)decays first by alpha decay, then beta decay. What is the final sotope (Some possibly important information about the atomic numbers of some elements: 81 I, 82Pb , 83Bi,S4f1>,8sAt, 86Rri, 87Fr, 88Ra.) . ~ ~ 2 \ '6 A Lf 2''t 0_ '":'>. . 1... :\:-? <X-( . 'is \ ~ e-t Y .-f I)()'ro~ <6"') 2-\ l)3. .-I a ~ ~ ,...
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This note was uploaded on 02/10/2011 for the course PHYS 14 taught by Professor Physcs14 during the Spring '09 term at Santa Monica.

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