ANS:A -

Thermal diffusivity (α) is given by the formula: α=ρ×cp​k​ Where:

• α is the thermal diffusivity (in 2/m2/s or 2/ft2/s),
• k is the thermal conductivity of the material (in W/m⋅K or /ℎBTU/hr⋅ft⋅°F),
• ρ is the density of the material (in 3kg/m3 or 3lb/ft3), and
• cp​ is the specific heat capacity of the material (in J/kg⋅K or BTU/lb⋅°F).

The thermal diffusivity represents the rate at which heat is conducted through a material relative to how it is stored within the material. It describes how quickly temperature changes can propagate through a substance. Materials with higher thermal diffusivities conduct heat more quickly.