Steel bars, each of length 3.0 m at 28°C, are to be used for constructing a rail line. If the linear expansivity of steel is 1.0 x 10-5°C, what is the safety gap that must be left between successive bars if the highest temperature expected is 40oC?
-
A.
1.2 x 10-1cm -
B.
8.4 x 10-2cm -
C.
7.2 x10-2cm -
D.
3.6 x 10-2cm -
E.
1.8 x 10-2cm
Correct Answer: Option D
Explanation
Gap ΔL = αL1Δθ = 1.0 x 10-5 x 3 x (40 – 28)
= 3.6 x 10-2