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Resistance of a metal wire of length 1m is 26Ω at 200C. If the diameter of the wire is 0.3mm, what will be the resistivity of the metal at that temperature? Predict the material of the wire. |
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Answer» Here, R= 26Ω, = 1m, d=0.3mm = 0.3 x 10-3m ∴ Radius, r = \(\frac{d}{2}\) = \(\frac{0.3\times\ 10^{-3}}{2}\) = 0.15 x 10-3m Area, A = πr2 = 3.14 x (0.15 x 10-3)2= 0.071 x 10-6m2 ∴ Resistivity, = \(\frac{RA}{l}\) = \(\frac{26 \times\ 0.71 \times \ 10^{-6}}{1}\) = 1.84 x10-6Ωm The material of the wire is of manganese. |
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