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JAMB Physics 2003 Question 20

Question 20

Thermal Expansion

On a fairly cool rainy day when the temperature is 20°C, the length of a steel railroad track is 20m. What will be its length on a hot dry day when the temperature is 40°C? [coefficient of linear expansion of steel = 11 × 10−6 K−1]

  1. A.20.013m
  2. B.20.009m
  3. C.20.004m
  4. D.20.002m
Show the answer and explanation

Answer: C (20.004m)

Explanation

Increase = αLΔθ = 11 × 10−6 × 20 × 20 = 0.0044 m, so the length is about 20.004 m.