Question Detail
Question
The steel bed of a suspension bridge is 300 m long at 20°C. If the temperature on a hot day reaches a maximum value of 45°C, compute the increase in length of the bridge. Take the coefficient of expansion (α) to be 12 × 10⁻⁶ /°C.
Correct Answer
Option B is the correct answer.
Detailed Explanation
ΔL = α L₀ ΔT = 12 × 10⁻⁶ × 300 × (45 - 20) = 12 × 10⁻⁶ × 300 × 25 = 12 × 10⁻⁶ × 7500 = 90000 × 10⁻⁶ = 0.09 m = 9 cm.
Hint
Use linear expansion formula: ΔL = α L₀ ΔT.