Physics Electronics PMDC Conceptual Practice
PMDC Verified Question 58 of 494
Under ideal reverse bias conditions, a semiconductor diode exhibits an effective electrical resistance that is:
A
Infinitely large (acting as an open switch)
B
Zero (acting as a closed switch)
C
Equal to its forward dynamic resistance
D
Linearly proportional to forward current
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Infinitely large (acting as an open switch)
Concept:

An ideal diode completely prevents current conduction under reverse bias, acting as an open circuit with infinite resistance.

Formula:

$$R_{\text{reverse, ideal}} = \infty$$

Solution:

  • Under reverse bias, majority carriers are pulled away from the junction, widening the depletion region.


  • An ideal diode permits zero reverse current (\( I = 0 \)), corresponding to an infinite reverse junction resistance.


Why other options are incorrect:

  • Option B: Zero resistance is the characteristic of an ideal diode under forward bias.


  • Option C: Practical diodes have forward resistances of a few ohms and reverse resistances in the mega-ohm range.


  • Option D: Forward current does not flow under reverse bias.

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 Electronics 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