5C Homework 9 - schriver PDF

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Homework 9

6/6/18, 2(18 PM

Homework 9 Due: 6:00pm on Monday, June 11, 2018 You will receive no credit for items you complete after the assignment is due. Grading Policy

Problem 29.8 is an energy-level diagram for a simple atom.

Part A What wavelengths appear in the atom's emission spectrum? Enter your answers in ascending order separated by commas. ANSWER:

λ=

nm

Part B What wavelengths appear in the atom's absorption spectrum? Enter your answers in ascending order separated by commas. ANSWER:

λ=

nm

Problem 29.11 https://session.masteringphysics.com/myct/assignmentPrintView?assignmentID=6345805

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Homework 9

The allowed energies of a simple atom are 0.0 eV , 5.5 collisionally excites the atom.

6/6/18, 2(18 PM

eV and 9.0 eV . An electron traveling at a speed of 1.9×106 m/s

Part A What is the minimum speed the electron could have after the collision? Express your answer with the appropriate units. ANSWER:

v=

Part B What is the maximum speed the electron could have after the collision? Express your answer with the appropriate units. ANSWER:

v=

Problem 29.16

Part A What quantum number of the hydrogen atom comes closest to giving a 580-nm -diameter electron orbit? Express your answer as an integer. ANSWER:

n=

WhatBisThis the electrons speed in this after state? Part question will be shown you

Problem 29.44 https://session.masteringphysics.com/myct/assignmentPrintView?assignmentID=6345805

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Homework 9

6/6/18, 2(18 PM

eV photon is emitted from a hydrogen atom.

A 3.13

Part A What is the Balmer formula n value corresponding to this emission? ANSWER:

n=

Part B What is the Balmer formula m value corresponding to this emission? ANSWER:

m=

Problem 29.60

Part A What is the energy of a hydrogen atom with a 1.69

nm diameter?

ANSWER:

E=

eV

Problem 29.61 A hydrogen atom in the ground state absorbs a 12.75 eV photon. Immediately after the absorption, the atom undergoes a quantum jump to the next-lowest energy level.

Part A What is the wavelength of the photon emitted in this quantum jump? Express your answer with the appropriate units. ANSWER:

https://session.masteringphysics.com/myct/assignmentPrintView?assignmentID=6345805

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Homework 9

6/6/18, 2(18 PM

λ=

Problem 30.30 The barium isotope 133 Ba has a half-life of 10.5 years. A sample begins with 1.0×1010 133 Ba atoms.

Part A How many are 133 Ba atoms left in the sample after 7 years. Express your answer using two significant figures. ANSWER:

N=

Part B How many are 133 Ba atoms left in the sample after 20 years. Express your answer using two significant figures. ANSWER:

N=

Part C How many are 133 Ba atoms left in the sample after 190 years. Express your answer using two significant figures. ANSWER:

N=

Problem 30.32

Part A How many half-lives must elapse until 80 % of a radioactive sample of atoms has decayed? https://session.masteringphysics.com/myct/assignmentPrintView?assignmentID=6345805

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Homework 9

6/6/18, 2(18 PM

Express your answer using two significant figures. ANSWER: t t1/2 =

Part B How many half-lives must elapse until 99 % of a radioactive sample of atoms has decayed? Express your answer using two significant figures. ANSWER: t t1/2 =

Problem 30.39 An investigator collects a sample of a radioactive isotope with an activity of 490,000 Bq . 48 hours later, the activity is 150,000 Bq.

Part A What is the half-life of the sample? Express your answer using two significant figures. ANSWER:

t1/2 =

h

Problem 30.65 All the very heavy atoms found in the earth were created long ago by nuclear fusion reactions in a supernova, an exploding star. The debris spewed out by the supernova later coalesced to form the sun and the planets of our solar system. Nuclear physics suggests that the uranium isotopes 235 U( t1/2 = 7.04 × 108 yr) and 238 U( t1/2 = 4.47 × 109 yr) should have been created in roughly equal amounts.

Part A Today, 99.28% of uranium is 238 U and 0.72% is235 U . How long ago did the supernova occur? ANSWER: https://session.masteringphysics.com/myct/assignmentPrintView?assignmentID=6345805

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Homework 9

t=

6/6/18, 2(18 PM

yr

Score Summary: Your score on this assignment is 0.0%. You received 0 out of a possible total of 50 points.

https://session.masteringphysics.com/myct/assignmentPrintView?assignmentID=6345805

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