Physics Current Electricity UHS 2023
PMDC Verified Question 27 of 112
A wire of uniform area of cross-section 'A', length 'L', and resistance 'R' is cut into two equal parts. What will happen to the resistivity of each part?
A
It will be doubled
B
It will be one fourth
C
It will be halved
D
It will remain the same
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: It will remain the same
Concept:

Resistivity is an intrinsic property characteristic of the specific material (e.g., copper, silver) and its temperature.

Solution:

  • Unlike Resistance (\(R\)), which depends on macroscopic dimensions like length and area, Resistivity (\(\rho\)) is purely determined by atomic structure.


  • Cutting the wire physically changes its length and halves its total resistance, but the material itself hasn't changed.


  • Therefore, the resistivity remains exactly the same.


Why other options are incorrect:

  • Opt A, B, C: These incorrectly assume resistivity is dimension-dependent like resistance.

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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