# Linear Thermal Expansion Coefficient

on . Posted in Thermodynamics

Linear thermal expansion coefficient, abbreviated as $$\overrightarrow{\alpha_l}$$  (Greek symbol alpha), also called coefficient of linear thermal expansion, is the ratio of the change in size of a material to its change in temperature.

## Linear thermal expansion coefficient Formula

$$\large{ \overrightarrow{\alpha_l} = \frac{ l_f \;-\; l_i }{ l_i \; \left( T_f \;-\; T_i \right) } }$$
Symbol English Metric
$$\large{ \overrightarrow{\alpha_l} }$$   (Greek symbol alpha) = linear thermal expansion coefficient $$\large{ \frac{in}{in\;F} }$$  $$\large{ \frac{mm}{mm\;C} }$$
$$\large{ l_f }$$ = final length $$\large{ft}$$ $$\large{m}$$
$$\large{ l_i }$$ = initial length $$\large{ft}$$ $$\large{m}$$
$$\large{ T_f }$$ = final temperature $$\large{F}$$ $$\large{C}$$
$$\large{ T_i }$$ = initial temperature $$\large{F}$$ $$\large{C}$$