Two cylindrical metal rods of 1 meter in length, one aluminum and one iron are heated from 20° to 80°. Given the coefficient of thermal expansion for aluminum and iron rods are 23.1×106 K⁻¹ and 11.8×10⁻⁶ K⁻¹ respectively, what is the difference in length of the two metal rods after heating (in mm)?
