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A current of 1.0 A is flowing through a copper wire of length 0.1 m and corss-section 1.0 X 10⁻⁶ m². (i) If the resistivity of copper be 1.7 x 10⁻⁸ Ω m, calculate the potential difference across the ends of a wire. (ii) Determine the drift velocity of electrons. [Density of copper = 8.9 x 10³ kg m⁻³, valancy of Cu = 1, atomic weight of copper = 63.5 g mol⁻¹, NA = 6.02 x 10²³ mo1⁻¹] |
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Answer» udent,◆ Answer -(i) Potential difference = 1.7×10^-3 V(ii) DRIFT velocity = 7.4×10^-5 m/s◆ Explaination -(i) Potential difference ACROSS wire is -V = IRV = Iρl/AV = 1 × 1.7×10^-8 × 0.1 / 10^-6V = 1.7×10^-3 V(ii) No of electrons per cu.m. is -n = valence × NA × d / MN = 1 × 6.022×10^23 × 8.9×10^3 / 63.5×10^-3n = 8.44×10^28 /m^3Drift velocity of electrons is GIVEN by -v = I/(nAe)v = 1 / (8.44×10^28 × 10^-6 × 1.6×10^-19)v = 7.4×10^-5 m/sHope this HELPS you... |
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