The thermal diffusivities for solids are generally

Thermal diffusivity is defined as the ratio of thermal conductivity to the product of density and specific heat capacity at constant pressure.

It indicates how quickly a material can conduct thermal energy relative to its ability to store it.

Solids generally have much higher thermal conductivity compared to liquids and gases, and although their density and specific heat may also be higher, the conductivity dominates, resulting in higher thermal diffusivity.

Liquids and gases typically have lower thermal conductivity and, in many cases, similar or lower specific heat, which makes their thermal diffusivity values lower than that of solids.

Option A: Less than those for gases
Incorrect. Gases usually have very low thermal diffusivity.

Option B: Less than those for liquids
Incorrect. Liquids have lower thermal diffusivity than most solids.

Option C: More than those for liquids and gases
Correct. Solids, particularly metals, typically have higher thermal diffusivity than both liquids and gases.

Option D: More or less same as for liquids and gases
Incorrect. Thermal diffusivity varies significantly among solids, liquids, and gases.

Correct Answer: Option C: More than those for liquids and gases