(a) A 35.5-m length of copper wire at 20.0°C has a radius of 0.31 mm. If a potential difference of 7.0 V is applied across the length of the wire, determine the current in the wire. (Use the values in the following table.) Resistivities and Temperature Coefficients of Resistivity for Various Materials (at 20°C) Resistivity (A - m) Temperature Coefficient of Resistivity [(°C)-1] Material Silver 1.59 x 10-8 3.8 x 10-3 Copper 1.7 x 10-8 3.9 x 10-3 Gold 2.44 x 10-8 3.4 x 10-3 Aluminum 2.82 x 10-8 3.9 x 10-3 Tungsten 5.6 x 10-8 4.5 x 10-3 Iron 10.0 x 10-8 5.0 x 10-3 Platinum 11 x 10-8 3.92 x 10-3 Lead 22 x 10-8 3.9 x 10-3 Nichrome 150 x 10-8 0.4 x 10-3 Carbon 3.5 x 10-5 -0.5 x 10-3 Germanium 0.46 -48 x 10-3 Silicon 640 -75 x 10-3 Glass 1010-1014 Hard rubber *1013 Sulfur 1015 Quartz (fused) 75 x 1016 A nickel-chromium alloy commonly used in heating elements. A (b) If the wire is heated to 34.0°C while the 7.0-V potential difference is maintained, what is the resulting current in the wire?

(a) A 35.5-m length of copper wire at 20.0°C has a radius of 0.31 mm. If a potential difference of 7.0 V is applied across the length of the wire, determine the current in the wire. (Use the values in the following table.) Resistivities and Temperature Coefficients of Resistivity for Various Materials (at 20°C) Resistivity (A - m) Temperature Coefficient of Resistivity [(°C)-1] Material Silver 1.59 x 10-8 3.8 x 10-3 Copper 1.7 x 10-8 3.9 x 10-3 Gold 2.44 x 10-8 3.4 x 10-3 Aluminum 2.82 x 10-8 3.9 x 10-3 Tungsten 5.6 x 10-8 4.5 x 10-3 Iron 10.0 x 10-8 5.0 x 10-3 Platinum 11 x 10-8 3.92 x 10-3 Lead 22 x 10-8 3.9 x 10-3 Nichrome 150 x 10-8 0.4 x 10-3 Carbon 3.5 x 10-5 -0.5 x 10-3 Germanium 0.46 -48 x 10-3 Silicon 640 -75 x 10-3 Glass 1010-1014 Hard rubber *1013 Sulfur 1015 Quartz (fused) 75 x 1016 A nickel-chromium alloy commonly used in heating elements. A (b) If the wire is heated to 34.0°C while the 7.0-V potential difference is maintained, what is the resulting current in the wire?

Physics for Scientists and Engineers: Foundations and Connections

1st Edition

ISBN:9781133939146

Author:Katz, Debora M.

Publisher:Katz, Debora M.

Chapter28: Current And Resistance

Section28.3: Current Density

Problem 28.3CE

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