Answer:
0.42 m
Explanation:
For thermal expansion, the formula used is as follows
L = L₀ ( 1 + α t )
L is length after rise of temperature by t , L₀ is length before rise of temperature , α is coefficient of thermal expansion and t is rise in temperature.
L - L₀ = L₀α t
Difference of length = L₀α t
L₀ = 1000 m , α = 10.5 x 10⁻⁶ , t = 40
Difference of length = 1000 x 10.5 x 10⁻⁶x 40
= 0.42 m .