Chemistry Solids UHS 2023
PMDC Verified Question 19 of 54
In metals, why electric conductivity decreases with the increases of temperature?
A
Because electron movement decrease with the increase of temperature
B
Because metal ions oscillations hinder electron movement
C
Because electron direction changes at high temperature
D
Because they pass heat current through collision of electrons
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Because metal ions oscillations hinder electron movement
Concept:
Metallic conduction relies on the free flow of a "sea of electrons" past positively charged metal kernels (ions) situated at the lattice points.

Solution:
  • As the temperature of a metal increases, the thermal energy is converted into kinetic energy.
  • This causes the positive metal ions at the lattice points to oscillate/vibrate much more vigorously around their mean positions.
  • These intense oscillations increase the frequency of collisions between the flowing free electrons and the vibrating metal ions.
  • This scattering essentially "hinders" the electron movement, increasing resistance and thus decreasing electric conductivity.


Why other options are incorrect:
  • A: The kinetic energy and movement of the electrons themselves actually increase with temperature, they just face more obstacles.
  • C, D: These do not accurately describe the mechanism of electrical resistance in metallic lattices.

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 Solids 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