NEET-XII-Physics
32: Electric Current in Conductors
- #6A wire of length 1 m and radius 0.1 mm has a resistance of 100 Ω. Find the resistivity of the material.Ans : Let ρ be the resistivity of the wire.
Given:
Length, l = 1 m
Radius, r = 0.1 × 10-3 m
Area, A = `` \,\mathrm{\,\pi \,}{r}^{2}``
Resistance, R = 1000 Ω
We know:
`` R=\rho \frac{l}{A}``
`` \Rightarrow \rho =\frac{RA}{l}``
`` =\frac{1000\times \,\mathrm{\,\pi \,}\times 0.1\times 0.1\times {10}^{-6}}{1}``
`` =\,\mathrm{\,\pi \,}\times {10}^{-6}\,\mathrm{\,\Omega m\,}``
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