Question
Download Solution PDFThe resistance of a copper wire decreases when ________ increases
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFThe resistance of a copper wire decreases when the diameter increases.
Explanation:
The resistance of copper is inversely proportional to the diameter of the wire hence when diameter decreases the resistance of a copper wire increases.
\(R = \frac{{\rho L}}{A}\)
And also copper has a positive temperature coefficient of resistance i.e. as temperature increases resistance increases.
\(R = {R_{ref}}\left[ {1 + \alpha \left( {T - {T_{ref}}} \right)} \right]\)Effect of temperature on resistance of different material:
Conductor: When the temperature of conducting material increases, the resistance of that particular material increases.
Insulator: When the temperature of the material increases, the resistance of that particular material decreases.
Semiconductor: When the temperature of the material increases, the resistance of that particular material decreases.
Carbon is a non-metal, semiconductor and its resistance decreases with an increase in temperature.
Constantan is a Nickel-Copper based alloy wire that has a high resistivity and is mainly used for thermocouples and electrical resistance heating. It contains 60% of nickel and 40%, copper. It has a constant resistivity over a wide range of temperatures.
Silver and copper are metal conductor which has a positive temperature coefficient which causes an increase in resistance due to an increase in temperature.Last updated on May 28, 2025
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