A scale made of material having coefficient of linear expansion $\left({\alpha }_s\right)$  at  $t_{i}C$. If  temperature is changed to $t_2\left(t_2>t_1\right)$ then error in measurement of scale is

$$\begin{gathered} coefficient of linear expansion is {\alpha }_s=\frac{∆L}{L∆temperature} \\ \Rightarrow ∆L={\alpha }_{s}L∆t \\ here L is initial length of scale \\ ∆L is change in length of scale \\ ∆t is change in temperature \end{gathered}$$