Physics Electronics PMDC Conceptual Practice
PMDC Verified Question 375 of 494
Which group of electronic devices is based directly on the operating principles of \( \text{P-N} \) junctions?
A
Semiconductor diodes, light emitting diodes (LEDs), and junction transistors
B
Carbon-composition resistors, air-core inductors, and ceramic capacitors
C
Electromechanical relays, incandescent lamps, and mechanical switches
D
Step-down transformers, variable rheostats, and fuse elements
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Semiconductor diodes, light emitting diodes (LEDs), and junction transistors
Concept:

The \( \text{P-N} \) junction is the fundamental building block of solid-state semiconductor devices.

Formula:

Qualitative concept / No formula required.

Solution:

  • Rectifier diodes, Zener diodes, and photodiodes utilize single \( \text{P-N} \) junctions.


  • Light Emitting Diodes (LEDs) and laser diodes use forward-biased \( \text{P-N} \) junctions for radiative recombination.


  • Bipolar Junction Transistors (BJTs) use two back-to-back \( \text{P-N} \) junctions (N-P-N or P-N-P).


Why other options are incorrect:

  • Options B, C, & D: Resistors, inductors, capacitors, relays, incandescent bulbs, and transformers are passive or electromechanical components that do not contain \( \text{P-N} \) semiconductor junctions.

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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