Steel bars each of length 3m at 28°C are to be used f...
Steel bars each of length 3m at 28°C are to be used for constructing a rail line. If the linear expansitivity of the steel is 1 x \(10^{-5}K^{-1}\),what is the safety gap that must be left between the successive bars if the highest temperature expected is 40°C?
1.2x \(10^{-1}cm\)
7.2x\(10^{-1}cm\)
6x\(10^{-1}cm\)
3.6x\(10^{-2}cm\)
1.8x\(10^{-1}cm\)
Correct answer is D
\(\alpha= \frac{\Delta{L}}{L_1\Delta\theta}; \Delta{L}=\alpha{L_1}\Delta\theta\Rightarrow 1.0\times 10^{-5}\times 300\times (40-28)= 0.036 or 3.6\times 10^{-2}\)