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
Verified Correct Answer: D.
Physical Principles & Numerical Solution
Gap ΔL = αL1Δθ = 1.0 x 10-5 x 3 x (40 - 28)
= 3.6 x 10-2
Source: Myschool Past Questions Archive (Record #24254)