Answer:
[tex]\Delta L = 4.2 m[/tex]
Explanation:
As per the formula of thermal expansion we know that
[tex]L = L_o(1 + \alpha\Delta T)[/tex]
so here we will have
[tex]L_o = 1400 m[/tex]
[tex]\alpha = 12 \times 10^{-6} per ^oC[/tex]
[tex]\Delta T = 250 degree C[/tex]
so here change in the length of the rod is given as
[tex]\Delta L = L - L_o[/tex]
[tex]\Delta L = L_o \alpha \Delta T[/tex]
[tex]\Delta L = 1400 (12 \times 10^{-6})(250)[/tex]
[tex]\Delta L = 4.2 m[/tex]