Question

define coefficient of linear expression write an expression for it give its unit

Answer 1

Dear student,

considering your question is about; "what is linear expansion, its unit and expression?"
here is the solution;

The coefficient of linear expansion of a substance is the ratio of the change in length to the original length per degree rise in temperature of a rod or a bar. It is a physical quantity depending on the nature of the material of the rod or bar. Its unit is K^-1 or ^oC^-1.
$$\begin{gathered} expression: \\ \frac{△l}{l}=\alpha △T \\ \alpha =\frac{△l}{l}\times \frac{1}{△T} \\ where, \\ △T=changeintemperature \\ △l=changeinlength \\ l=originallength \\ \alpha =coefficientoflinearexpansion \end{gathered}$$

Regards,