Physics Nuclear Physics KU 2024
PMDC Verified Question 3 of 98
Mass number A refers to ____
A
Number of electrons
B
Number of nucleons
C
Number of neutrons
D
Number of protons
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Number of nucleons


Concept:

An atom's identity and mass are governed by the particles inhabiting its nucleus.

Solution:

  • The nucleus contains protons and neutrons. Together, these heavy particles are collectively referred to as nucleons.


  • The Mass Number (represented by the symbol \(A\)) is simply the integer sum of the protons and neutrons combined.


  • Therefore, mass number literally refers to the total number of nucleons in the nucleus.


Why other options are incorrect:

Electrons have negligible mass and don't factor into the mass number. Option D defines the Atomic Number (\(Z\)). Option C represents only a fraction of the mass.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

Previous Question All Nuclear Physics MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App