Superficial expansion refers to the increase in the surface area of a solid when it is heated. It depends on the material’s nature and the temperature change. The coefficient of superficial expansion is used to quantify this increase and is approximately twice the linear expansion coefficient of the material.
Thermal properties of matter deal with how materials respond to heat. It includes concepts like temperature expansion specific heat and the laws of thermodynamics. When heat is added or removed from a body it results in changes in temperature or volume. Understanding these properties helps in various engineering and scientific applications.
It is the fractional change in the surface area of a substance for a unit change in temperature, when heated or cooled at constant pressure. It is defined mathematically as:
α = (1/A) * (dA/dT)
where,
– α is the coefficient of superficial expansion
– A is the initial surface area
– dA is the change in surface area
– dT is the change in temperature.
The units of α are per degree Celsius (°C⁻¹) or per Kelvin (K⁻¹).
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