Radius of a sphere is 100 cm at 0°C and 100.1 cm at 100°C. Coefficient of cubical expansion of the sphere is

Given that R₁ = 100cm, R₂ = 100.1cm 
t₁ = 0^oC, t₂ = 100^oC  
we have
$$\begin{gathered} \mathrm{\alpha }=\frac{{\mathrm{R}}_2-{\mathrm{R}}_1}{{\mathrm{R}}_1\left(∆\mathrm{t}\right)}=\frac{10.1-100}{100\left(100\right)}=10 \mathrm{x} {10}^{-6}/{}^{o}C \\ \mathrm{then} \mathrm{\gamma }=3\mathrm{\alpha }=3(10 \mathrm{x} {10}^{-6})=30 \mathrm{x} {10}^{-6}{/}^{\mathrm{o}}\mathrm{C} \end{gathered}$$