Physics Nuclear Physics MDCAT 2016
PMDC Verified Question 65 of 98
Thorium is transformed after the emission of \(\beta\)-particle into:
A
Bismuth
B
Polonium
C
Protactinium
D
Palladium
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Protactinium


Concept:

Beta (\(\beta^{-}\)) decay increases the atomic number (\(Z\)) of the parent element by exactly 1, moving it one space forward on the periodic table.

Solution:

  • Thorium (Th) has an atomic number of \(Z = 90\).


  • After emitting a beta particle, a neutron becomes a proton, so \(Z_{new} = 90 + 1 = 91\).


  • The element with atomic number 91 is Protactinium (Pa).


Why other options are incorrect:

Bismuth is \(Z=83\). Polonium is \(Z=84\). Palladium is \(Z=46\). None of these match \(Z=91\).

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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