Question

Which substance is known for very high thermal conductivity at room temperature?

• A. Silicon
• B. Teflon
• C. Graphene
• D. Iron

Hint:

The high thermal conductivity of graphene makes it a prime candidate for heat sinks and thermal management systems in high-performance microelectronics.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks to identify the material among the choices that possesses an exceptionally high thermal conductivity value at room temperature.

Step 2: Detailed Explanation:

• Thermal Properties of Graphene: Graphene is a two-dimensional sheet of carbon atoms hybridized in an \( \text{sp}^2 \) configuration arranged in a hexagonal honeycomb lattice.
It exhibits an outstanding experimental thermal conductivity of approximately \( 3000 \text{ to } 5000 \text{ W/m}\cdot\text{K} \) at room temperature.
This remarkably high value is due to the strong covalent carbon-carbon bonds and the highly efficient, unhindered propagation of lattice vibrations (phonons) through its flat, defect-free 2D structure.

• Comparison with Other Materials:
-

Silicon (Option A) is a semiconductor with a moderate thermal conductivity of around \( 150 \text{ W/m}\cdot\text{K} \).
-

Teflon (Option B, PTFE) is a polymer. Its disordered, amorphous molecular structure makes it a thermal insulator with an extremely low thermal conductivity of \( \sim 0.25 \text{ W/m}\cdot\text{K} \).
-

Iron (Option D) is a metal with a thermal conductivity of approximately \( 80 \text{ W/m}\cdot\text{K} \), which is significantly lower than that of copper (\( \sim 400 \text{ W/m}\cdot\text{K} \)) and orders of magnitude lower than graphene.


Step 3: Final Answer:
Therefore, Graphene is known for its exceptionally high thermal conductivity at room temperature, matching Option (C).