The resistivity of a wire is determined from the relation

PHYSICS · Subjective · CBSE · Physics · Units and Measurements · Units and Measurements

Problem

The resistivity ρ\rho of a wire is determined from the relation ρ=RAL\rho = \dfrac{R A}{L}. The following measured values are obtained in a laboratory experiment: R=(24.5±0.5) ΩR = (24.5 \pm 0.5)\,\Omega, A=(5.0±0.1)×10−7 m2A = (5.0 \pm 0.1) \times 10^{-7}\,\text{m}^2, L=(1.20±0.01) mL = (1.20 \pm 0.01)\,\text{m}. (i) Calculate the value of ρ\rho. (ii) Determine the fractional (relative) uncertainty in ρ\rho. (iii) Hence obtain the absolute uncertainty in ρ\rho and quote the final result with an appropriate number of significant figures.

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