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Nuclear Physics MCQs for MDCAT Practice

Physics section, Nuclear Physics chapter. Up to eight free sample questions, each with the correct answer and a worked explanation. The full chapter opens in the app.

The bank has 1,143 active questions on this chapter. Your first 500 practice attempts are free, and every attempt includes a worked explanation.

  1. Question 1
    Structure of Nucleus successfully explained by:
    • Bohr
    • Millikan
    • J.J. Thomson
    • Rutherford (correct answer)
    Correct answer: D
    Rutherford's gold foil experiment elucidated the nuclear model of the atom, revealing a dense, positively charged nucleus.
  2. Question 2
    When gamma photon is entered in nucleus it _______
    • De-excites the atom
    • Excites the atom (correct answer)
    • Scatters by atom
    • None of these
    Correct answer: B
    Gamma photons entering a nucleus transfer energy, causing excitation, not de-excitation or simple scattering.
  3. Question 3
    Radioactive 90Sr has a half-life of 30 years. What percent of a sample of 90Sr will remain after 60 years?
    • 0%
    • 50%
    • 25% (correct answer)
    • 75%
    Correct answer: C
    Understand radioactive decay and half-life: After 60 years (two half-lives), only 25% of 90Sr remains.
  4. Question 4
    Which type of radiation do explosions give off?
    • Neutron radiation
    • Alpha radiation
    • Gamma radiation
    • All of them (correct answer)
    Correct answer: D
    Nuclear explosions release a spectrum of ionizing radiation, including neutrons, alpha particles, and gamma rays, making 'all of them' the correct answer.
  5. Question 5
    The half-life of a radioactive isotope is 140 days. In how many days does the decay rate of a sample of this isotope decrease to one-fourth of its initial decay rate?
    • 35
    • 280 (correct answer)
    • 105
    • 210
    Correct answer: B
    Understand how radioactive decay rate relates to half-life; a decrease to one-fourth requires two half-lives.
  6. Question 6
    What is a radioactive tracer? Describe one application in i medicine.
    • radioactive tracer is a substance that emits radiation and is used to detect leaks in underground pipes. (correct answer)
    • radioactive tracer is a substance that emits radiation and is used to sterilize medical equipment.
    • radioactive tracer is a substance that emits radiation and is used to treat cancer by destroying tumor cells.
    • radioactive tracer is a substance that emits radiation and is used to measure the age of rocks and fossils.
    Correct answer: A
    Radioactive tracers are substances used in medical imaging to track biological processes, with applications in diagnosing diseases like cancer.
  7. Question 7
    A nucleus emits: 2 alpha particles 1 beta minus particle Net change in atomic number is:
    • Z-4
    • Z-3 (correct answer)
    • Z-2
    • Z-1
    Correct answer: B
    Understand how alpha and beta particle emissions affect a nucleus's atomic number (Z) to predict the net change.
  8. Question 8
    A source contains initially N0 nuclei of a radioactive nuclide. How many of these nuclei have decayed after a time interval of three half-lives?
    • N0/8
    • 2N0/3
    • N0/3
    • 7N0/8 (correct answer)
    Correct answer: D
    After three half-lives, 7/8ths of the initial radioactive nuclei have decayed, leaving only 1/8th remaining.

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Read the full Nuclear Physics chapter notes: Nuclear Physics notes. Or browse every chapter.