With an increase in the temperature of a body, there is an increase in its dimension too. This property is known as thermal expansion. The thermal expansion of a body is a function of temperature.
One of the common examples of thermal expansion is seen while opening a tight metal jar lid. People often loosen a tight metal jar lid by holding it under hot water. By doing so, the metal of the lid and the glass of the jar expand because the hot water adds energy to their atoms. The metal expands more, as compared to glass, and thus gets loose.
Types of Thermal Expansion
Linear expansion
Now, let us consider a rod at a temperature T and suppose its length is L at the same temperature. When the temperature is increased to T + ΔT, the length also increases to L + ΔL.
ΔL/L = αLΔT
Where,
ΔL change in length, L = original length, ΔT = change in temperature, αL = linear coefficient of thermal expansion.
Area expansion
A0(l+βt)
Here, β is the coefficient of surface expansion.
Volume expansion
∆v = Vy∆t
Here, y is the coefficient of volume expansion.
Video Lesson – Thermal Expansion
Solved Problems on Thermal Expansion
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Frequently Asked Questions on Thermal Expansion
Define thermal expansion.
An increase in the size of a body due to an increase in temperature is called thermal expansion.
What is linear expansion?
When a solid is heated, and its length increases, the expansion is called linear expansion.
What is superficial or area expansion?
When a solid is heated, and its area increases, the thermal expansion is called superficial or area expansion.
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