Physics Nuclear Physics MDCAT 2011
PMDC Verified Question 92 of 98
The ratio of the rate of decay of a parent atom to the number of radioactive nuclei present at that time is equal to:
A
Half-life of radioactive element
B
Decay constant of radioactive element
C
Mean life
D
Activity if radioactive element
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Decay constant of radioactive element


Concept:

This question relies directly on the mathematical definition of the radioactive decay law.

Formula:

$$ \text{Rate of decay} = \left| \frac{\Delta N}{\Delta t} \right| = \lambda N $$

Solution:

  • The question asks for the ratio of the Rate of Decay to the Number of Nuclei (\(N\)).


  • Dividing both sides by \(N\): $$ \frac{\text{Rate of decay}}{N} = \lambda $$


  • The symbol \(\lambda\) represents the decay constant.


Why other options are incorrect:

Half-life is \(0.693/\lambda\). Mean life is \(1/\lambda\). Activity is the rate of decay itself, not the ratio.

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