Electronics Information:
Which of the following has the least resistance?
A. wood
B. iron
C. rubber
D. silver
The Correct Answer and Explanation is:
The correct answer is D. Silver.
Explanation:
Resistance in a material depends on its ability to resist the flow of electric current, which is determined by factors such as the material’s inherent properties (specifically, its resistivity), temperature, and dimensions (length and cross-sectional area). Materials with low resistivity are good conductors of electricity, while materials with high resistivity are poor conductors or insulators.
- Wood (A): Wood is a poor conductor of electricity, making it an insulator. Its resistivity is relatively high, meaning it strongly resists the flow of electric current. The resistance of wood is significantly higher than that of metals or other conductive materials.
- Iron (B): Iron is a good conductor of electricity but not as good as some other metals. It has a lower resistivity than non-metals like wood or rubber, but its resistance is still considerably higher than that of more conductive metals like silver or copper.
- Rubber (C): Rubber is an insulator with very high resistivity. It is used in electrical applications to insulate wires and prevent the unintended flow of electric current. Rubber’s resistance is much higher than that of metals.
- Silver (D): Silver is one of the best conductors of electricity, with extremely low resistivity. It is often used in high-quality electrical connectors and components due to its excellent ability to allow the free flow of electric charge. Silver’s resistivity is lower than that of almost all other materials, meaning it has the least resistance among the options.
The resistance ( R ) of a material is calculated using the formula:
[
R = \rho \times \frac{L}{A}
]
Where:
- ( R ) is the resistance,
- ( \rho ) is the resistivity,
- ( L ) is the length of the material,
- ( A ) is the cross-sectional area.
Since silver has the lowest resistivity (( \rho )), it offers the least resistance to electrical current, making it the correct answer.