Which type of materials has high resistivity or low conductivity?
Tungsten
Resistivity Explained
Resistivity is a fundamental property of a material that describes how strongly it opposes the flow of electric current. A material with high resistivity offers significant opposition to electrical current. Conductivity, on the other hand, measures how easily a material allows electric current to flow. These two properties are inversely related, which can be expressed using the formula:
$ \text{Conductivity} (\sigma) = \frac{1}{\text{Resistivity} (\rho)} $
Materials with high resistivity inherently have low conductivity, and vice versa.
Conductivity Vs Resistivity Comparison
We are looking for a material among the options that has high resistivity, meaning it has low conductivity.
- Copper (Cu): Widely used in electrical wiring due to its excellent conductivity and very low resistivity.
- Aluminium (Al): Also a very good conductor, slightly less conductive than copper but lighter and cheaper. It has low resistivity.
- Gold (Au): An excellent conductor, highly resistant to corrosion, often used in specialized electronic components. It has low resistivity.
- Tungsten (W): Known for its high melting point and strength. Compared to copper, aluminium, and gold, Tungsten has a significantly higher resistivity. This property is utilized in applications like the filaments of incandescent light bulbs, where electrical resistance causes the filament to heat up and emit light.
Material Resistivity Comparison
The approximate values of resistivity for these materials at room temperature (20°C) illustrate the differences:
| Material | Resistivity ($ \rho $) in $ \Omega \cdot m $ |
| Copper | $ 1.68 \times 10^{-8} $ |
| Aluminium | $ 2.82 \times 10^{-8} $ |
| Gold | $ 2.44 \times 10^{-8} $ |
| Tungsten | $ 5.60 \times 10^{-8} $ |
As the table shows, Tungsten has a higher resistivity value than Copper, Aluminium, and Gold.
Tungsten: High Resistivity Example
Based on the comparison, Tungsten is the material among the given options that exhibits high resistivity and consequently low conductivity relative to the others. Its electrical resistance is a key characteristic exploited in specific technological applications.
Important Questions from Basic Electricity
In a series lamp circuit, each bulb is rated for 2 V. Calculate the number of bulbs to be connected in series to run on a 110 V AC line.
For domestic wiring purposes, how are circuits connected?
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1 kWh is equivalent to:
A choke has characteristics of______
