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. Bismuth
- B. Protactinium
- C. Polonium
- D. Palladium
Explanation: Thorium-234 has a half-life of 24.1 days, emitting a beta particle that results in its transformation to protactinium-234.
Correct answer: Protactinium- A. Bismuth
- B. Protactinium
- C. Polonium
- D. Palladium
Explanation: The emission of gamma rays, or γ-rays, from radioactive elements is a process that typically occurs when an unstable nucleus undergoes…
Correct answer: Polonium- A. A proton
- B. A neutron
- C. An alpha particle
- D. a beta particle
Explanation: Beta decay is a radioactive decay in which a beta ray is emitted from an atomic nucleus.
Correct answer: a beta particle- A. Increase
- B. Remain the same
- C. Decrease
- D. Increase or decrease depending upon the temperature of the substance
Explanation: Radioactivity is always random and spontaneous. Random means one cannot know precisely when the next decay will happen, though one can…
Correct answer: Remain the same- A. 83Bi212
- B. 81Bi210
- C. 85Bi210
- D. None of these
Explanation: When a β-particle, which is an electron, is emitted from the nucleus during beta decay, a neutron is transformed into a proton.
Correct answer: 83Bi212- A. one Becquerel
- B. One curie
- C. One-half life
- D. None of above
Explanation: One becquerel is the quantity of a radioactive element in which there is one atomic disintegration per second.
Correct answer: One curie- A. 92U235
- B. 92U236
- C. 92U238
- D. 92U239
Explanation: 92U235 is the only naturally occurring isotope of uranium that is fissile (able to fission with slow neutrons).
Correct answer: 92U235- A. No charge
- B. Non-material nature
- C. Small size
- D. Lighter particles
Explanation: Gamma rays have higher penetrating power than alpha and beta particles due to their lack of charge.
Correct answer: No charge- A. Cyclotron
- B. Betatron
- C. Accelerator
- D. Nuclear reactor
Explanation: The device in which the controlled fission chain reaction is maintained is called a nuclear reactor.
Correct answer: Nuclear reactor- A. 90Rn^220
- B. 86Rn^222
- C. 89Rn^226
- D. 90Rn^222
Explanation: When an alpha particle is emitted, the mass number of the daughter nucleus will decrease by 4, and the charge number will decrease by 2.
Correct answer: 86Rn^222- A. fission
- B. beta decay
- C. alpha radiation
- D. gamma radiation
Explanation: URANIUM-238 : Mass number : 238 Atomic number : 92 THORIUM-234 : Mass number : 234 Atomic number: 90 From above, it is clear that mass…
Correct answer: alpha radiation- A. Alpha radiation
- B. Beta radiation
- C. Gamma radiation
- D. X radiation
Explanation: Alpha radiations are doubly positively charged helium nuclei. When such radiation is emitted from a radioactive element, its mass number…
Correct answer: Alpha radiation- A. one curie
- B. one Becquerel
- C. one half life
- D. all of these
Explanation: In radioactivity, activity is defined as disintegrations per second. The SI unit of Activity is Becquerel (Bq).
Correct answer: one Becquerel- A. Electron
- B. Positron
- C. Proton
- D. Neutron
Explanation: In the nuclear reaction 11Na24 → 12Mg24 + X, the atomic number increases by one, indicating a beta-minus decay.
Correct answer: Electron- A. curie
- B. Becquerel
- C. Tesla
- D. both a and b
Explanation: The activity of a radioactive material, which represents the rate of decay of radioactive nuclei, can be expressed in units of both curie…
Correct answer: both a and b- A. 83Bi214
- B. 84Po214
- C. 82Pb214
- D. 41TI214
Explanation: In beta decay, a neutron in the nucleus is transformed into a proton and a beta particle (an electron) is emitted.
Correct answer: 82Pb214- A. Temperature
- B. Pressure
- C. Humidity level
- D. None of the above
Explanation: Radioactive decay is the process by which an unstable atomic nucleus loses energy by emitting radiation.
Correct answer: None of the above- A. 47Ag111
- B. 47Ag110
- C. 47Ag112
- D. 49In111
Explanation: In β⁻ emission (beta minus decay): An electron (β⁻ particle) is emitted.→ Atomic number increases by 1, mass number stays same.So the…
Correct answer: 47Ag111- A. α-particles
- B. electrons and neutrons
- C. Positron and neutrinos
- D. Only neutrons
Explanation: Nuclear fission is when heavy unstable nuclei disintegrate to two lighter nuclei along with the emission of a neutron, electron, and energy.
Correct answer: electrons and neutrons- A. Straight
- B. Erratic
- C. Circular
- D. Elliptical
Explanation: The path traced by beta particles in air is erratic. This is because beta particles are high-speed electrons emitted during radioactive…
Correct answer: Erratic