What is the correct sequence of resistivity of silver, nichrome and glass at room temperature?

Question

Prepp Team · Accepted Answer

Understanding Resistivity and Material Types

Resistivity is a fundamental property of a material that measures how strongly it resists the flow of electric current. Materials can be broadly classified based on their resistivity:

Conductors: Materials with very low resistivity, allowing current to flow easily. Examples include metals like silver, copper, and gold. Silver has exceptionally low resistivity, making it an excellent conductor.
Resistors/Alloys: Materials with higher resistivity than pure conductors but lower than insulators. Alloys, which are mixtures of metals, often fall into this category and are used in heating elements and resistors. Nichrome is an example of such an alloy.
Insulators: Materials with very high resistivity, preventing or severely limiting the flow of electric current. Examples include glass, rubber, plastic, and wood.

Comparing Resistivity of Silver, Nichrome, and Glass

To determine the correct sequence of resistivity for silver, nichrome, and glass at room temperature, we need to consider their classifications:

Silver: A pure metal and one of the best electrical conductors. Its resistivity is very low.
Nichrome: An alloy of nickel and chromium, commonly used in heating elements. It has significantly higher resistivity than typical conducting metals like silver or copper.
Glass: A non-metallic solid, which is a very good electrical insulator. Its resistivity is extremely high compared to metals and alloys.

Based on these classifications and properties, the order of increasing resistivity is:

Silver (lowest resistivity - conductor)
Nichrome (intermediate resistivity - alloy/resistor)
Glass (highest resistivity - insulator)

We can represent this sequence using the less than ('<') symbol, where a smaller value precedes a larger value:

\(\text{Resistivity of Silver} < \text{Resistivity of Nichrome} < \text{Resistivity of Glass}\)

This corresponds to the sequence: Silver < Nichrome < Glass.

Resistivity Values (Approximate at Room Temperature)

Here is a table showing approximate resistivity values to illustrate the differences:

Material	Approximate Resistivity (\(\rho\)) at Room Temperature
Silver	\(1.59 \times 10^{-8} \, \Omega \cdot m\)
Nichrome	\(1.10 \times 10^{-6} \, \Omega \cdot m\)
Glass	\(10^{10} - 10^{14} \, \Omega \cdot m\)

As you can see from the table, the resistivity values clearly follow the order: Silver is the lowest, Nichrome is much higher than Silver, and Glass is extremely high compared to both.

Conclusion: Correct Resistivity Sequence

Therefore, the correct sequence of resistivity from lowest to highest for silver, nichrome, and glass at room temperature is Silver < Nichrome < Glass.

Revision Table: Key Concepts

Concept	Definition/Explanation	Relation to Resistivity
Resistivity	A material's inherent ability to oppose electric current flow.	Higher resistivity means greater opposition to current.
Conductor	Material allowing easy current flow.	Low resistivity. Example: Silver.
Insulator	Material preventing current flow.	Very high resistivity. Example: Glass.
Alloy (Resistor)	Mixture of metals; often used where controlled resistance is needed.	Resistivity usually between conductors and insulators. Example: Nichrome.

Additional Information: Factors Affecting Resistivity

While comparing materials at room temperature gives us a standard order, it's important to know that resistivity can be affected by several factors:

Temperature: For most conductors, resistivity increases with temperature. For semiconductors and some insulators, resistivity can decrease with temperature.
Impurities: Adding impurities to a pure metal (forming an alloy, for example) generally increases its resistivity compared to the pure metal. This is why nichrome (an alloy) has higher resistivity than pure silver or nickel.
Mechanical Stress: Applying stress can sometimes affect the resistivity of materials.

Understanding these factors helps explain why different materials have such vastly different electrical properties and how those properties can change under different conditions.