Practice!

Sample Problem

The coefficient of linear expansion for cobalt is 1.2 × 10-5C-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?

Solution

We will use the formula ΔL = αL0 ΔT. We plug in the known values, α = 1.2 × 10-5, L0 = 10, ΔT = 100, and we get that ΔL = (1.2 × 10-5) (10) (100) = 0.012 m, or 12 mm.