Free Radioactive Decay MCQs with Answers
82 Radioactive Decay MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Radioactive decay is the spontaneous transformation of unstable nuclei, described by decay constant, activity, half life and the exponential decay law. Work includes alpha, beta and gamma emissions, decay equations and remaining nuclei, with half life distinguished from the time required for complete decay.
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- A. K-shell electron
- B. The decay of neutron
- C. Pre existing electron in nucleus
- D. The decay of proton
Explanation: The explanation is given below: Beta (β) particles in radioactivity originate from the decay of certain types of atomic nuclei.
Correct answer: The decay of neutron- A. Stable
- B. Unstable
- C. Small
- D. None
Explanation: Correct. Elements with atomic number Z > 82 are typically unstable and undergo radioactive decay.In summary, the correct option is **b.
Correct answer: Unstable- A. s- 1
- B. s
- C. N
- D. m
Explanation: The unit of decay constant is inverse seconds (s⁻¹). It is also sometimes represented in other inverse time units such as per minute, per…
Correct answer: s- 1- A. 90
- B. 91
- C. 89
- D. 92
Explanation: An α-particle decreases the atomic number bt 2 and mass number by 4. And β-particle emission increases the atomic number by 1.
Correct answer: 91- A. One decay per second
- B. Two decay per second
- C. Three decay per second
- D. Four decay per second
Explanation: One Becquerel (Bq) is defined as one decay per second. It's the SI unit of radioactivity, and it measures the rate of radioactive decay.If…
Correct answer: One decay per second- A. energy.
- B. particle.
- C. electric charge.
- D. ionising radiation.
Explanation: Ionising radiation: A Geiger Muller counter, often called a Geiger counter, is specifically designed to detect ionising radiation.
Correct answer: ionising radiation.- A. A
- B. B
- C. C
- D. D
Explanation: The question describes the nucleus ⁸²Pb²¹⁴ emitting an electron. This process is known as beta-minus decay (β⁻ decay).In beta-minus decay…
Correct answer: D- A. A
- B. B
- C. C
- D. D
Explanation: Gamma (γ) rays are a form of electromagnetic radiation, meaning they are pure energy and travel at the speed of light, which is the…
Correct answer: C- A. I only.
- B. III only.
- C. I and II.
- D. II and III.
Explanation: When an alpha particle encounters an atom, it eliminates neutrons and electrons.
Correct answer: II and III.- A. 1 atomic mass unit (u)
- B. 2 atomic mass units (u)
- C. 4 atomic mass units (u)
- D. 8 atomic mass units (u)
Explanation: The correct answer is Option C: 4 atomic mass units (u). When a radioactive nucleus emits an alpha particle, it loses two protons and two…
Correct answer: 4 atomic mass units (u)- A. I only
- B. III only
- C. I and II
- D. II and III
Explanation: Alpha particles (Option I) and beta particles (Option II) are charged particles, hence they are affected by electric and magnetic fields.
Correct answer: I and II- A. controlled fusion reaction
- B. controlled fission reaction
- C. uncontrolled fusion reaction
- D. uncontrolled fission reaction
Explanation: The correct answer is Option C: uncontrolled fusion reaction. In the context of an atomic bomb explosion, the rapid and uncontrolled…
Correct answer: uncontrolled fusion reaction- A. Mass number remains 226, atomic number becomes 89
- B. Mass number becomes 225, atomic number remains 88
- C. Mass number becomes 227, atomic number decreases to 87
- D. Mass number remains 226, atomic number decreases to 87
Explanation: When a beta particle is emitted, a neutron in the nucleus is transformed into a proton.
Correct answer: Mass number remains 226, atomic number becomes 89- A. I only.
- B. II only.
- C. I and III.
- D. II and III.
Explanation: The correct answer is I only. The Wilson cloud chamber operates on the principle that supersaturated vapours condense more easily on ions.
Correct answer: I only.- A. A) Gamma rays have less penetration power than alpha particles.
- B. B) Gamma rays have less penetration power than beta particles.
- C. C) Gamma rays have the same penetration power as alpha particles.
- D. D) Gamma rays have greater penetration power than both alpha and beta particles.
Explanation: Gamma rays are electromagnetic radiation with no mass and no charge, allowing them to penetrate materials far more deeply than charged…
Correct answer: D) Gamma rays have greater penetration power than both alpha and beta particles.- A. Definitely Alpha-rays
- B. Definitely Beta-rays
- C. Both Alpha and Beta rays
- D. Either Alpha or Beta rays
Explanation: Both alpha and beta particles are affected due to the magnetic field and so both rays may be produced, but not simultaneously.
Correct answer: Either Alpha or Beta rays- A. 6C12
- B. 6C13
- C. 6C14
- D. 6C12 , 6C14
Explanation: Carbon-14 is a radioactive isotope of carbon that is used in carbon dating, also known as radiocarbon dating.
Correct answer: 6C14- A. Paper
- B. Water
- C. Air
- D. All of these options are correct
Explanation: Beta rays have a high enough frequency, hence, energy to pass through all these mediums without being blocked
Correct answer: All of these options are correct- A. An electron which was existing outside the nucleus.
- B. An electron which was existing inside the nucleus.
- C. An electron emitted by the nucleus as a of the decay of neutrons inside the nucleus.
- D. A pulse of electromagnetic waves.
Explanation: An unstable atom can attain stability by radioactive decay such as alpha, beta or gamma decay.
Correct answer: An electron emitted by the nucleus as a of the decay of neutrons inside the nucleus.- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Explanation:γ radiation causes no change in the atomic mass or atomic number.
Correct answer: Option D