Physics Current Electricity NUMS 2024
PMDC Verified Question 19 of 112
The substance having negative temperature coefficient are:
A
Insulators
B
Conductors
C
Semi-conductor
D
Alloys
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Semi-conductor
Concept:

Materials respond to heat differently based on their electron valence bands.

Solution:

  • Semi-conductors naturally have very few free charge carriers at room temperature.


  • When heated, the thermal energy breaks bonds, suddenly flooding the material with electrons and holes.


  • This surge in charge carriers vastly decreases the overall resistance.


  • Because resistance drops as temperature rises, this mathematical relationship is termed a negative temperature coefficient.


Why other options are incorrect:

  • Opt B & D: Conductors and most alloys have positive coefficients (resistance increases with heat).


  • Opt A: While insulators do technically decrease resistance slightly when heated, semiconductors are the defining textbook standard for this specific measurable coefficient property.

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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