Density of a substance at 0°C is 10.6 gm/c.c and at 100°C is 10 gm/c.c. coefficient of linear expansion of solid is

$\mathrm{\rho }$₁ =10.6gm / cc, $\mathrm{\rho }$₂ = 10gm / cc ; $∆$t = 100 
we have
 $$\begin{gathered} \mathrm{\gamma }=\frac{{\mathrm{\rho }}_1-{\mathrm{\rho }}_2}{{\mathrm{\rho }}_2∆\mathrm{t}}=\frac{10.6-10}{10\left(100\right)}\Rightarrow 3\mathrm{\alpha }=\frac{0.6}{{10}^3} \because \gamma =3\alpha \\ \mathrm{\alpha }=2 \mathrm{x} {10}^{-4}=0.0002/°\mathrm{C} \end{gathered}$$