Electrical materials – identify the poorest electrical conductor among common options Among the listed materials, which one is the poorest conductor of electricity at room temperature and is therefore often used for resistive heating elements?

Introduction:
Conduction ability is quantified by electrical resistivity. Pure metals like silver, copper, and aluminum exhibit low resistivity and therefore good conductivity. Certain alloys, however, are deliberately formulated to have much higher resistivity to serve as stable resistive elements in heaters and precision resistors—Nichrome is a classic example.

Given Data / Assumptions:

• Room-temperature comparison of bulk conductors.
• Purity and typical commercial composition considered.
• No special cryogenic or high-temperature anomalies included.

Concept / Approach:

Nichrome (nickel–chromium alloy) has a resistivity roughly two orders of magnitude higher than copper and significantly above aluminum and silver. Its oxidation resistance and mechanical stability at high temperature make it ideal for heating elements where high resistance and durability are desired. Therefore, in the list, Nichrome is the poorest conductor (highest resistivity).

Step-by-Step Solution:

Verification / Alternative check:

Heater wires and toasters commonly employ Nichrome because of its high resistivity and oxidation resistance, confirming its poor conductivity relative to common metals.

Why Other Options Are Wrong:

Aluminum and copper are good conductors used for power conductors; “All of the above” cannot be correct; silver is one of the best conductors.

Common Pitfalls:

Assuming density correlates with conductivity; confusing thermal and electrical conductivity trends.

Final Answer:

Nichrome