Physics Nuclear Physics SZABMU 2023
PMDC Verified Question 20 of 98
The unit of radio activity is curie which is equal to:
A
\( 7.3 \times 10^{10} \text{ disintegration / s} \)
B
\( 3.7 \times 10^{10} \text{ disintegration / s} \)
C
\( 3.7 \text{ disintegration / s} \)
D
\( 7.3 \text{ disintegration / s} \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: \( 3.7 \times 10^{10} \text{ disintegration / s} \)


Concept:

The Curie (Ci) is a standardized, historical unit of radioactivity derived from the behavior of Radium.

Solution:

  • Originally, 1 Curie was defined as the decay rate of exactly one gram of Radium-226.


  • Through modern physical measurement, this value has been rigidly standardized to exactly \( 3.7 \times 10^{10} \text{ disintegrations per second} \).


  • This massive number shows why measuring activity in Becquerels (1 decay/s) often requires prefixes like Mega or Giga.


Why other options are incorrect:

Option A (7.3) is a fabricated distractor. Options C and D completely miss the massive exponent (\(10^{10}\)) necessary for macroscopic radiation amounts.

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.

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