Physics Current Electricity SZABMU 2024
PMDC Verified Question 2 of 112
In any electric circuit, power output (\( P_{out} \)) will be maximum when ____. (Whereas R = external resistance, r = internal resistance)
A
\( R = 0 \) but \( r \neq 0 \)
B
\( r = 0 \) but \( R \neq 0 \)
C
\( R = \infty \) and \( r = 0 \)
D
\( R = r \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: \( R = r \)
Concept:

The maximum power transfer theorem defines the absolute limit of power a source can deliver to a load.

Solution:

  • The theorem states that to obtain maximum external power from a source with a fixed internal resistance (\(r\)), the external load resistance (\(R\)) must be exactly matched to it.


  • Therefore, maximum power occurs strictly when \( R = r \).


Why other options are incorrect:

  • Opt A: If \(R=0\) (short circuit), voltage drops to zero across the load, yielding zero power output.


  • Opt B: While an ideal theoretical battery (\(r=0\)) delivers more total power unconditionally, the theorem asks for the condition on any given real circuit.


  • Opt C: Infinite resistance means zero current flow, thus zero power.

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 Current Electricity 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