Physics Nuclear Physics MDCAT 2012
PMDC Verified Question 88 of 98
Which of the following effect is observed due to emission of \(\beta\) during the phenomenon of radioactivity?
A
A increases by 1 and Z remains same
B
Z decreases by 1 and A remains same
C
Z increases by 1 and A remains same
D
A decreases by 1 and Z remains same
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Z increases by 1 and A remains same


Concept:

Beta minus (\(\beta^{-}\)) decay occurs when a neutron decays into a proton and an electron.

Formula:

$$ _{Z}^{A}\text{X} \rightarrow _{Z+1}^{A}\text{Y} + _{-1}^{0}\text{e} + \bar{\nu}_e $$

Solution:

  • Because a neutron turns into a proton, the number of protons (atomic number \(Z\)) increases by 1.


  • The total number of nucleons (protons + neutrons) remains exactly the same, so the mass number (\(A\)) is unchanged.


Why other options are incorrect:

Option A is physically impossible (mass cannot increase during natural decay). Option B describes positron (\(\beta^{+}\)) decay or electron capture. Option D is incorrect as mass number doesn't drop by 1.

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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