Chapter 7 Test: Radioactivity

17 Questions | Total Attempts: 116

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Nuclear Science Quizzes & Trivia

Test taking strategy advice! 1. Read all questions carefully and try to eliminate choices that are obviously wrong. 2. If stuck on a question, skip it for now and come back later (answer each Q eventually). 3. In essays, think before you write and be sure to answer the question. 4. Please ask for clarification if something is unclear to you. 5. Take your time and do your best. You’ll never regret doing the best that you can.


Questions and Answers
  • 1. 
    Background measurements and counting rates from a paper filter attached to a vacuum cleaner for one hour were taken at three locations.  The results are shown on the table below.  The background was not subtracted.  All rates are in counts per minute.     Location X Location Y Location Z Background Filter 18 19 16 85 31 29  
  • 2. 
    The table below summarizes the results of an experiment in which a Geiger counter operated with no substances held near it, then with equal masses of compounds of elements W, X, Y, and Z held near it at equal distances.     Compound Elements in Compound Counts during a one-minute interval Trial I Trial II Trial III None 1 2 3 4 None WX WY ZX ZY 6 91 97 8 9 13 100 90 9 7 5 94 99 8 6  
  • 3. 
       
  • 4. 
    PLEASE TYPE YOUR ANSWERS TO THE FOLLOWING QUESTIONS IN THE SPACE PROVIDED, YOU MAY USE A SEPARATE SHEET TO WORK OUT THE ANSWER.  
  • 5. 
    Explain your answer to number 13.  Use complete sentences.  
  • 6. 
    In class we measured the radiation given off by a small sample of radioactive barium.  We noted that     the number of counts decreased over time (i.e., it showed a “half-life”).  Why does the radiation     decrease as a radioactive sample ages?  In other words, what is happening to the radioactive material     that causes it to give off less radiation as time passes?  USE COMPLETE SENTENCES.  
  • 7. 
    The table below shows the net counting rate for radioactive material collected on filter paper.     Time (min.) Net counting rate (counts/min) 0 20 40 60 80 100 120 440 340 230 170 95 60 45 On graph paper, plot the data on a graph that shows the net counting rate as a function of time. Draw a smooth curve that represents the general trend of the data (a “curve of best fit”).               Note: This graph is worth 3 points
  • 8. 
    What would the 'net counting rate' be after 160 minutes, and why?  
  • 9. 
    Six background readings were taken with a Geiger counter over one-minute intervals.  The numbers of counts recorded per minute were: 22, 18, 22, 26, 22, and 28.  What do you think would have been the result of the next measurement, in counts/min? 
  • 10. 
    From your curve, determine the approximate half-life of this material.
  • 11. 
    Which of the following materials are able to block some form of radiation?
    • A. 

      Lead foil

    • B. 

      Skin

    • C. 

      Clothing

    • D. 

      All of the above

    • E. 

      None of the above

  • 12. 
    Samples of three substances (I, II, and III) were left several days on a piece of photographic film wrapped in light-tight paper, as shown in figure (a).  The appearance of the film after being developed is shown in figure (b).  Based on this which of these substances seems to be the most radioactive?  
    • A. 

      I, II, and III

    • B. 

      I and III only

    • C. 

      I only

    • D. 

      II only

    • E. 

      III only

  • 13. 
    A sample of radioactive material is held a certain distance away from a Geiger counter.  Which of the following procedures would not affect the counting rate?  
    • A. 

      Placing a 6-foot-thick iron and concrete wall between the sample and the counter.

    • B. 

      Lowering the temperature of the sample

    • C. 

      Reducing the mass of the sample

    • D. 

      Waiting a billion years and coming back to test it again

  • 14. 
    A background measurement lasting one hour gave 15 counts/min.  Shortly after the measurement was completed, another background measurement lasting just one minute found 10 counts.  How would you explain the difference between the two results?  
    • A. 

      Something must have blocked the radiation from reaching the counter in the second measurement.

    • B. 

      Fewer counts are expected in 60 seconds than an hour.

    • C. 

      The difference of 5 counts/min was due to the presence of radon.

    • D. 

      Radioactivity is not perfectly predictable. Therefore the number of counts measured in a short time span may or may not match up with the long-term average.

  • 15. 
    When a radioactive substance is placed in a cloud chamber, we can actually see the evidence that  . . .
    • A. 

      One substance is changing into another substance.

    • B. 

      Radioactivity was discovered by humanity in the late-1800s.

    • C. 

      The substance is not pure; it is a mixture.

    • D. 

      Radioactive decay releases tiny particles--individual atoms.

    • E. 

      Dry ice is really frozen carbon dioxide.

  • 16. 
    At which location or locations was radioactive material floating in the air?
    • A. 

      Location X

    • B. 

      Location Y

    • C. 

      Location Z

    • D. 

      Location Y and Z

    • E. 

      Location X and Z

  • 17. 
    What conclusion can be reached based on the data from location Z?  
    • A. 

      The filter has a negative net count which means the air removed radiation from it.

    • B. 

      The filter has a net count of 29, and thus is radioactive.

    • C. 

      The filter has a net count of basically zero which means there was no radioactive material floating in the air.

    • D. 

      The Geiger counter needs a new battery.

  • 18. 
    From the results of this experiment, which element would probably be gone if we came back and tested again in 500 million years?  
    • A. 

      W, X, and Y only

    • B. 

      W only

    • C. 

      X only

    • D. 

      Y only

    • E. 

      All of the elements W, X, Y, and Z

  • 19. 
    Suppose a chunk of compound XY equal to the mass of the samples used above was held at the same distance from the counter.  The counter is run for one minute.  What range of counts per minute would you expect to see?  
    • A. 

      5 to 13

    • B. 

      10 to 26

    • C. 

      91 to 100

    • D. 

      182 to 200

    • E. 

      No counts

  • 20. 
    The type of radiation most able to pass through objects is: 
    • A. 

      Alpha radiation

    • B. 

      Beta radiation

    • C. 

      Gamma radiation

    • D. 

      Delta radiation

  • 21. 
    During a background measurement, a Geiger counter counted 1440 counts in 60 minutes.  What was the background radiation?  
  • 22. 
    The table below summarizes the results of an experiment in radioactivity. Compound Elements in compound Radioactivity as determined by a Geiger counter 1 Actinium, bromine Radioactive 2 Potassium, bromine Radioactive 3 Barium, bromine Non-radioactive 4 Uranium, chlorine Radioactive From the results of this experiment alone, which elements are definitely NOT radioactive?
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