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Author Question: A radioactive material initially is observed to have an activity of 1000 decays/sec. If nine hours ... (Read 53 times)

vicotolentino

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on: Jul 28, 2018
A radioactive material initially is observed to have an activity of 1000 decays/sec. If nine hours later it is observed to have an activity of 125 decays/s, what is its half-life?
 a. 1/2 hour
  c. 3 hours
  b. 8 hours
  d. 1 hour

Question 2

Neglecting recoil of the gold nucleus, how much kinetic energy must an alpha particle (charge = 2  1.6  10-19 C) have to approach to within 1.95  10-14 m of a gold nucleus (charge = 79  1.6  10-19 C)? (ke = 8.99  109 Nm2/C2 and 1 MeV = 1.6  10-13 J)
 a. 14.6 MeV
  c. 18.2 MeV
  b. 11.7 MeV
  d. 22.7 MeV


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joechoochoy

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Reply #1 on: Jul 28, 2018
Answer to Question 1

C

Answer to Question 2

B


vicotolentino

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Reply #2 on: Jul 28, 2018
TY


joechoochoy

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Reply #3 on: Jul 28, 2018
You're welcome


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