Answer:
ΔL = 3.704 10⁻⁴ mm
Step-by-step explanation:
The body when heated increases the distance between its atoms, which results in a linear expansion of the bodies, which is described in the first approximation by the expression
ΔL = α L Δt
Where alf is the linear expansion coefficient, L the initial length, Dt the temperature variation and DL the length variation
ΔL = 5.50 10⁻⁷ 3.49 (213 - 20)
ΔL = 3.704 10⁻⁴ mm