A steel rail of length 5 m and area of cross section 40 cm^2 is prevented from expanding along its length while the temperature rises by 10°C. If…

A steel rail of length $\displaystyle 5$ m and area of cross section $\displaystyle 40 \mathrm{~cm}^2$ is prevented from expanding along its length while the temperature rises by $\displaystyle 10$°C. If coefficient of linear expansion and Young's modulus of steel are $\displaystyle 1.2 \times 10^{-5} \mathrm{~K}^{-1}$ and $\displaystyle 2 \times 10^{11} \mathrm{Nm}^{-2}$ respectively, the force developed in the rail is approximately :