The coefficient of linear expansion for cobalt is 1.2 × 10^{-5}C^{-1}. If the length of a cobalt bar is 10 meters at 12°C, what is the change in its length when it is at 112° C?

We will use the formula ΔL = αL_{0} ΔT. We plug in the known values, α = 1.2 × 10^{-5}, L_{0} = 10, ΔT = 100, and we get that ΔL = (1.2 × 10^{-5}) (10) (100) = 0.012 m, or 12 mm.