Two wires of equal length, one of aluminium and the other of iron, have the same resistance. Which of the two wires is lighter? Hence explain why aluminium wires are preferred for overhead power cables? (Relative density of aluminium = iron 10 x 108 °C-'). 2.7, that of 2.7 x 108 °c", that of iron = 8.0, resistivity of aluminium = %3D

Two wires of equal length, one of aluminium and the other of iron, have the same resistance. Which of the two wires is lighter? Hence explain why aluminium wires are preferred for overhead power cables? (Relative density of aluminium = iron 10 x 108 °C-'). 2.7, that of 2.7 x 108 °c", that of iron = 8.0, resistivity of aluminium = %3D

Physics for Scientists and Engineers, Technology Update (No access codes included)

9th Edition

ISBN:9781305116399

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter27: Current And Resistance

Section: Chapter Questions

Problem 27.34P: Review. Ail aluminum rod has a resistance of 1.23 at 20.0C. Calculate the resistance of the rod at...

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When a straight wire is heated, its resistance changes according to the equation R = R0 [1 + (T T0)] (Eq. 17.7), where is the temperature coefficient of resistivity. (a) Show that a more precise result, which includes the length and area of a wire change when it is heated, is R=R0[1+(TT0)][1+(TT0)][1+2(TT0)] where is the coefficient of linear expansion. (See Topic 10.) (b) Compare the two results for a 2.00-m-long copper wire of radius 0.100 mm, starting at 20.0C and heated to 100.0C.
What current flows through a 2.54-cm-diameter rod of Pure silicon that is 20.0 cm long, when 1.00103 V is applied to it? (Such a rod may be used to make nuclear- particle detectors, for example.)
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