What is the resistivity of a wire when voltage increases?

Thread starter Jaccobtw
Start date Mar 26, 2022
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Resistivity Voltage Wire

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SUMMARY

The resistivity of a wire is calculated using the formula ρ = V/I, where V is voltage and I is current. In the discussion, the user mistakenly computed conductivity instead of resistivity, leading to confusion. The correct approach requires careful attention to units, as they are crucial in electrical calculations. The user initially arrived at a value of 1250, which was incorrect due to the oversight in unit application.

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Understanding of Ohm's Law (V = IR)
Familiarity with electrical units (voltage, current, resistance)
Knowledge of resistivity and conductivity concepts
Basic algebra for manipulating equations

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Study the relationship between resistivity and conductivity in materials
Learn how to properly apply units in electrical calculations
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Students in physics or electrical engineering, educators teaching electrical concepts, and professionals involved in materials science or electrical design.

Mar 26, 2022

Jaccobtw

Homework Statement: A wire has a uniform cross sectional area of 1cm^2 and a length of 1m. When the potential difference across the wire is increased by 16V, the current increases by 2A. What is the resistivity of the wire?

Relevant Equations: $$R = \frac{l}{\sigma A}$$

Divide volts by current to get resistance which is 8. Multiply both sides by 8 and sigma to get:

$$\frac{1m}{8\Omega\times10^{-4}m^2} = 1250$$

But this answer seems to be way off. How did I go wrong? Thanks