What is the resistivity of a wire when voltage increases?

AI Thread Summary
The discussion centers on calculating the resistivity of a wire when voltage increases. It highlights that resistance can be found by dividing volts by current, leading to a calculation involving conductivity rather than resistivity. The initial calculation appears to be incorrect due to missing units and confusion between conductivity and resistivity. Emphasizing the importance of units in calculations is crucial for accurate results. Understanding the distinction between these two electrical properties is essential for proper analysis.
Jaccobtw
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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
 
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First you are lacking units. Units are important.

Second, you have computed conductivity, not resistivity.
 
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