Metal rods of length 20m each are laid end to end to form...
Metal rods of length 20m each are laid end to end to form a bridge at 25oC. What gap will be provided between consecutive rails for the bridge to withstand 75oC?
[Linear expansivity of the material = 2.0 x 10-5K-1
0.20m
0.22m
0.25m
0.02m
Correct answer is D
Safety gap = expansion of the rod
= α×L0×Δt
where α = linear expansivity of the material
L0 = Initial length of the material
Δt = Change in temperature
∴ The safety gap = 2 \times 10^{-5} \times 20 \times (75 - 25)
= 2 \times 10^{-5} \times 10^3
= 2 \times 10^{-2} m
= 0.02 m