Quiz  /  Half Life Class 9 MCQ Questions With Answers

  • 1. 
    Gamma rays have

  • no mass
  • a huge mass
  • a small mass
  • an average mass

  • 2. 
    The half life of iodine-131 is 8.040 days. What percentage of an iodine-131 sample will remain after 40.20 days?

  • 312.5%
  • 31.25%
  • .3125%
  • 3.125%

  • 3. 
    146C has a half life of 5730 years, how many years would it take the 4.0 g sample to decay to 0.25 g?

  • 4 years
  • 5730 years
  • 22,920 years
  • 28,650 years

  • 4. 
    The time it takes for a radioactivity level to drop by a half is is the sample's ___________________.

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

  • 5. 
    _________________ is when two smaller atoms combine to form a larger more stable atom

  • fission
  • fusion

  • 6. 
    What makes an element radioactive?

  • When it's nuclei expands
  • When it's electrons explode
  • When it's nuclei behave
  • When it's nuclei decay

  • 7. 
    Which order is correct for the most to least ionising

  • Alpha-Beta-Gamma
  • Beta-Alpha-Gamma
  • Gamma-Beta-Alpha
  • Gamma-Alpha-Beta

  • 8. 
    If one has 12 kg of Polonium and it undergoes two half-lives, how much do you have left?

  • 12 kg
  • 3 kg
  • 6 kg

  • 9. 
    In alpha decay, the atomic number...

  • increases by 2
  • decreases by 2
  • increases by 4
  • decreases by 4

  • 10. 
    Which type of radiation has 2 protons and 2 neutrons

  • Alpha
  • Beta
  • Gamma
  • Neutron

  • 11. 
    Describe the structure of an alpha particle.

  • a fast-moving electron
  • 2 protons and 2 neutrons
  • a slow-moving neutron
  • a hydrogen nucleus

  • 12. 
    Which type of radiation penetrates paper and skin, but can be stopped by a thin sheet of metal?

  • Alpha
  • Beta
  • Gamma

  • 13. 
    What is emitted during Gamma Radiation?

  • Particles.
  • Protons
  • Beta Rays.
  • Gamma Rays.

  • 14. 
    You find a rock sample with radioactive atoms present.  If 25% of the original radioactive atoms were present, how many half-lives has the rock been around for? (Hint, at Half-Life = 0, you start with 100%)

  • zero
  • 1
  • 2
  • 3

  • 15. 
    If the radioactivity of a substance starts at 500 Bequerels. What will the radioactivity be after one half life?

  • 1000
  • 250
  • 125
  • 500

  • 16. 
    Technetium-99 isotope has a half-life of 6.0 hours. If 100.0 mg were injected into a patient how much remains after 18 hours?

  • 33.0 mg
  • 12.5 mg
  • .33 mg
  • 15.8 mg
  • 50.0 mg

  • 17. 
    Which type of radiation penetrates paper and skin, or a thin sheet of metal, but can be stopped by a sheet of lead, or thick concrete?

  • Alpha
  • Beta
  • Gamma

  • 18. 
    Name given to the atoms that are left after an atom decays.

  • Parent
  • Daughter
  • Leftovers

  • 19. 
    Which type of radiation is used by smoke detectors?

  • Alpha
  • Beta
  • Gamma
  • Neutron

  • 20. 
    Why does beta decay occur?

  • The nucleus is too large to be stable
  • The proton to neutron ratio is unstable
  • The nucleus is in an excited state. This usually follows other types of decay.
  • The nucleus is too small to be viable by itself
  • The isotope has too many high energy electrons

  • 21. 
    Which of these defines irradiation

  • Radioactive particles are on the object
  • An object is exposed to radiation nearby
  • An object is radioactive itself
  • Radioactive particles don't affect the object

  • 22. 
    Using this graph, what is the half-life of the strontium?

  • 10 years
  • 25 years
  • 50 years
  • 150 years

  • 23. 
    If one-fourth of the carbon-14 is remaining then how many half-lives have passed?

  • 1
  • 2
  • 3
  • 4

  • 24. 
    What percentage of rubidium-87 atoms will be left after four half lives?

  • 25.0%
  • 12.5%
  • 6.25%
  • 3.125%

  • 25. 
    Electron capture produces the same product as

  • alpha decay.
  • beta decay.
  • positron emission.
  • nuclear fusion reactions.

  • 26. 
    What is the only difference between two different isotopes of the same element?

  • Number of neutrons
  • Number of protons
  • Number of electrons
  • Size of atom

  • 27. 
    Radiation can cause what?

  • Superpowers
  • Cancer
  • Headaches
  • The flu
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