Which of the following materials is likely to have the highest thermal conductivity?

Explanation:

Thermal Conductivity of Materials

• Thermal conductivity is a physical property of materials that measures their ability to conduct heat. It is defined as the amount of heat (in watts) that passes through a material with a given area and thickness when a temperature difference exists across the material. The unit of thermal conductivity is watts per meter per degree Celsius (W/m·°C).

Working Principle:

• The working principle of thermal conductivity involves the transfer of heat energy from the hotter part of the material to the cooler part. This transfer occurs through the vibration of atoms and molecules or through the movement of electrons in the case of metals. Materials with high thermal conductivity can transfer heat quickly and efficiently, while materials with low thermal conductivity are better insulators.

Aluminium:

• Aluminium is known for its high thermal conductivity. It is a metal with a thermal conductivity value of approximately 237 W/m·°C, which is significantly higher compared to other materials listed in the options. This high thermal conductivity makes aluminium an excellent material for applications requiring efficient heat transfer, such as heat exchangers, cooling systems, and electronic components.
• Aluminium's ability to conduct heat quickly is due to the presence of free electrons that can move easily through the material, transferring thermal energy from one part to another. This property is particularly useful in industries where rapid heat dissipation is critical to prevent overheating and maintain optimal performance.

Additional Information Option 1: Rubber

• Rubber is an insulating material with a very low thermal conductivity. Its thermal conductivity value is typically around 0.1-0.2 W/m·°C, which means it does not conduct heat well. This property makes rubber suitable for applications requiring thermal insulation, such as in the manufacture of heat-resistant gloves, mats, and seals.

Option 2: Air

• Air also has low thermal conductivity, approximately 0.024 W/m·°C. This makes it a poor conductor of heat and an excellent insulator. Air is commonly used in insulating applications, such as in double-glazed windows, where the trapped air layer helps reduce heat transfer between the interior and exterior of buildings.

Option 4: Wood

• Wood has a moderate thermal conductivity, typically around 0.12-0.15 W/m·°C. While not as insulating as rubber or air, wood does not conduct heat as efficiently as metals like aluminium. Wood’s thermal conductivity depends on its density and moisture content, but it is generally used in applications where moderate insulation is required, such as in building construction and furniture making.