When a radioactive nucleus emits an alpha particle, its atomic mass drops by
Correct answer: C. 4 atomic mass units (u)
- 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 neutrons, resulting in a decrease of 4 atomic mass units. Options A and B underestimate the change, while Option D overestimates it. The correct calculation accounts for the total mass of the two protons and two neutrons in the alpha particle.
Last updated
About Radioactive Decay
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.
Practise Nuclear Physics
1,254 free Nuclear Physics MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Physics questions like this
Physics is on 13 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
Related questions
A nucleus emits a radiation neither its, mass no. nor charge no. change in the radiation is:
A particle was ejected from the nucleus of an atom in a radioactive decay and the active number of the atom increased. The particle was probably:
A radioactive isotope 'W' decays to 'X' which decays to 'Y' and 'Y' decays to 'Z' as represented by the figure below. What is the change in the atomic number from 'W' to 'Z'?
According to the equation AZ X → Y + 3 α particles, what are the atomic and mass numbers of 'Y'?
An alpha particle is emitted from 88Ra226. What is the mass and atomic number of the daughter nucleus ?