Physics Current Electricity ETEA 2023
PMDC Verified Question 37 of 112
A wire of length L has resistivity is \(\rho\), If the wire is divided in two halves, then resistivity of each halve is:
A
\(\rho/2\)
B
\(\rho\)
C
\(2\rho\)
D
\(\rho/3\)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: \(\rho\)
Concept:

Resistivity (\(\rho\)) is an intensive property; it depends entirely on the material's atomic composition and temperature, not on macroscopic size.

Solution:

  • No matter how you cut, stretch, or bend the wire, the specific nature of the material does not change.


  • Therefore, cutting the wire in half leaves the resistivity constant as \(\rho\).


Why other options are incorrect:

  • Opt A: Half the length halves the Resistance (\(R\)), not Resistivity.


  • Opt C & D: Dimensionally scaling an intrinsic property is incorrect.

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