Quiz  /  Radioactivity Class 9 MCQ Questions With Answers

  • 1. 
    What is a PRO about nuclear energy?

  • The amount of energy produced far excess what is produced using fossil fuels.
  • It is very safe and stable
  • Both of these are true

  • 2. 
    What is the role of the moderator in an nuclear reactor?

  • Increase kinetic energy of neutrons
  • Watch out for nasty nasty comments posted by the neutrons
  • Slow neutrons to thermal neutrons so they can be absorbed by uranium
  • absorb neutrons so they do not go to create a chain reaction

  • 3. 
    The amount of time it takes for half of the nuclei in a sample to undergo radioactive decay is

  • nuclear stability
  • nuclear instability
  • beta decay
  • half life

  • 4. 
    Which of the above graphs shows how the activity of a sample varies with time?

  • A
  • B
  • C
  • D

  • 5. 
    What form of radiation should a medical tracer emit?

  • alpha
  • beta
  • gamma
  • any of these

  • 6. 
    Which type(s) of radiation is a fast moving electron?

  • alpha
  • beta
  • gamma
  • alpha and beta
  • beta and gamma

  • 7. 
    The half-life of a substance is

  • the amount of substance left after it has decayed
  • the time it takes for half of the isotope to decay
  • the time it takes for half the mass to have radiated away
  • the mass of half of the isotope after decaying

  • 8. 
    The three types of nuclear radiation in order of decreasing penetrating power are

  • alpha, beta, gamma
  • alpha, gamma, beta
  • beta, alpha, gamma
  • gamma, alpha, beta

  • 9. 
    What is the major drawback to fission power?

  • Radioactive Waste
  • CO2 Emissions
  • SO2 Emissions
  • All of the Above

  • 10. 
    Which of the above best describes the words 'contamination' and irradiation'?

  • A
  • B
  • C
  • D

  • 11. 
    A certain radioactive sample has a half life of 2 years. After 6 years, how much of the sample is left?

  • 1/2
  • 1/3
  • 1/16
  • 1/8

  • 12. 
    The top number in this isotope notation is

  • the mass number
  • the atomic number
  • the atomic mass
  • the neutron number

  • 13. 
    ___________ starts the fission of a uranium atom.

  • Energy
  • Protons
  • One Neutron
  • All of the above

  • 14. 
    After 4 half-lives, 1g of a sample of Krypton-85 is left. What was the original mass of the sample?

  • 16g
  • 32g
  • 0.0625g
  • 4g

  • 15. 
    __________________ is the process in which two or more smaller nuclei combine to create a larger, more stable nuclei.

  • Nuclear Decay
  • Nuclear Fission
  • Nuclear Fusion
  • None of the above

  • 16. 
    A sample of 16 g of radioactive substance X has a half-life of 2 hours. What percentage of the sample is left after 6 hours?

  • none
  • 12.5 %
  • 25 %
  • 33.3 %

  • 17. 
    The centre of an atom is called

  • the electron
  • the proton
  • the nucleus
  • the neutron

  • 18. 
    Look at the diagram of an atom of a common element. What is the atomic number?

  • 3
  • 4
  • 7
  • 10

  • 19. 
    Ash was found to have 12.5% as much carbon-14 as found in similar ash. How long ago was the ash formed? The half-life of C-14 is 5730 years

  • 14080 years
  • 11460 years
  • 17190 years
  • 2865 years

  • 20. 
    Where does radioactivity have application in our lives?

  • Medicine
  • Energy (electricity)
  • Agriculture
  • All of the above

  • 21. 
    How many neutrons does the isotope of lithium have?

  • 8
  • 3
  • 4
  • 5

  • 22. 
    What change takes place to an atom during beta decay?

  • A proton changes into a neutron
  • A proton changes into an electron
  • An electron changes into a neutron
  • A neutron changes into a proton

  • 23. 
    Alpha particles are nuclei are

  • Helium
  • Iron
  • Carbon
  • Uranium

  • 24. 
    The rate at which a radioactive element decays is its ____.

  • quarter life
  • whole life
  • wonderful life
  • half life

  • 25. 
    The weakest radioactive emission is

  • alpha
  • beta
  • gamma

  • 26. 
    Which type(s) of radiation is the most ionising?

  • alpha
  • beta
  • gamma
  • alpha and beta
  • beta and gamma

  • 27. 
    What is the role of the control rods in a nuclear reactor?

  • Absorb Gamma Radiation
  • Release Alpha Particles
  • Fuse Unstable Nuclei
  • Absorb Neutrons

  • 28. 
    How many protons does this isotope of titanium have?

  • 48
  • 22
  • 26
  • 70

  • 29. 
    If the half life of a radioactive element is 100yrs, how long would it take for the radioactivity to reduce by one half?

  • 200yrs
  • 100yrs
  • 50yrs
  • 300yrs

  • 30. 
    A helium nucleus with two protons and two neutrons is called a(n) ____.

  • alpha particle
  • electroscope
  • beta particle
  • gamma ray
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