. What is Thermal Expansion

Best Answer

Thermal expansion can be defined as expansion due to increase in temperature. When temperature of a body increases, the distance between any two points on the object increases. The expanded object is like a photographic enlargement. Figure shows a plate with a hole in it. The hole expands in the same proportion as the metal, it does not get smaller.



At atomic level, thermal expansion may be explained by considering how the potential energy of the atoms varies with distance. The equilibrium position of an atom will be at the minimum of the potential energy well if the well is symmetric. But if the potential energy curve is asymmetric about the r0, then the average position of an atom will not be at the minimum point. When the temperature is raised the amplitude of the vibration increases and the average position is located at a greater inter-atomic separation. This increased separation is certified as expansion in the material.



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