Physics Current Electricity DUHS 2022
PMDC Verified Question 67 of 112
When different resistors are connected across the terminal of a battery:
A
Its emf remains same but terminal potential difference changes
B
Both emf and terminal potential difference changes
C
Its emf changes but terminal potential difference remains the same
D
Both emf and terminal potential difference remains the same
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Its emf remains same but terminal potential difference changes
Concept:

Electromotive force (EMF) is an intrinsic property of the battery chemistry, whereas terminal potential difference (\(V_t\)) depends on the current flowing through the circuit.

Formula:

$$ V_t = E - Ir $$

Solution:

  • Because EMF (E) is fixed by the chemical reaction of the cell, it remains the same regardless of the external circuit.


  • When you connect different external resistors, the total equivalent resistance changes, causing the total current (\(I\)) to change.


  • Since \(I\) changes, the internal voltage drop (\(Ir\)) changes, meaning the terminal potential difference changes. This makes Option A correct.


Why other options are incorrect:

  • Opt B, C, D: All incorrectly assert that EMF changes or that terminal voltage remains immune to current variations.

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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