# What is the resistivity of a wire when voltage increases?

• Jaccobtw
In summary, resistivity is a measure of a material's ability to resist the flow of electric current and is represented by the Greek letter rho (ρ). It is directly proportional to voltage and can be affected by factors such as material, length, cross-sectional area, and temperature. The resistivity of a wire can be measured using a multimeter and is important in determining the efficiency and effectiveness of electrical systems and devices.
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

First you are lacking units. Units are important.

Second, you have computed conductivity, not resistivity.

DaveE and Jaccobtw

## 1. What is resistivity?

Resistivity is a measure of a material's ability to resist the flow of electric current. It is a property of the material itself and is measured in ohm-meters (Ωm).

## 2. How is resistivity related to voltage?

Resistivity is directly proportional to voltage. This means that as the voltage increases, the resistivity of a material also increases.

## 3. What factors affect the resistivity of a wire?

The resistivity of a wire is affected by its length, cross-sectional area, and the material it is made of. Temperature can also affect resistivity, as some materials have a higher resistivity at higher temperatures.

## 4. How is the resistivity of a wire measured?

The resistivity of a wire can be measured by applying a known voltage to the wire and measuring the resulting current. The resistivity can then be calculated using Ohm's Law (resistivity = voltage/current).

## 5. Why is knowing the resistivity of a wire important?

Knowing the resistivity of a wire is important for understanding its electrical properties and how it will behave in a circuit. It is also essential for designing and building efficient and safe electrical systems.

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