Which of the following factors does NOT affect the thermal diffusivity of a material?  

Explanation:

Thermal Diffusivity

• Thermal diffusivity is a material-specific property that measures the rate at which heat moves through a material. It is a key parameter in heat transfer analysis and is defined as the ratio of thermal conductivity to the product of density and specific heat capacity at constant pressure. Mathematically, it is expressed as:

\(α = \frac{k }{ (ρ \times c_p)}\)

where:

• α is the thermal diffusivity (m²/s)
• k is the thermal conductivity (W/m·K)
• ρ is the density of the material (kg/m³)
• c_p is the specific heat capacity at constant pressure (J/kg·K)

Factors Affecting Thermal Diffusivity:

From the definition above, it is clear that thermal diffusivity depends on three main factors:

1. Thermal conductivity of the material
2. Density of the material
3. Specific heat capacity of the material