WAEC Physics questions: Thermal expansion

11 questions with answers and explanations. Tap an option to check yourself.

1. Question 1· Thermal expansion· WAEC

   A thick glass cup may crack when hot water is poured into it because

   • Athe water is too heavy
   • Bglass contracts when heated
   • Cthe inner surface expands more than the outer surface
   • Dglass is a good conductor

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   Explanation and discussion

2. Question 2· Thermal expansion· WAEC

   Gaps are left between railway lines to

   • Adrain water
   • Breduce weight
   • Csave metal
   • Dallow for expansion in hot weather

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   Explanation and discussion

3. Question 3· Thermal expansion· WAEC

   A metal rod 2 m long is heated through 50 K. If its linear expansivity is 1.2 × 10⁻⁵ K⁻¹, find the increase in length.

   • A1.2 × 10⁻⁴ m
   • B1.2 × 10⁻³ m
   • C6.0 × 10⁻³ m
   • D2.4 × 10⁻³ m

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4. Question 4· Thermal expansion· WAEC

   Because of the anomalous expansion of water, ponds freeze

   • Afrom the top downwards, so fish survive below
   • Bfrom the bottom upwards
   • Call at once
   • Dnever

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5. Question 5· Thermal expansion· WAEC

   Why does a pond freeze from the top downwards?

   • AWater below 4 °C is less dense and stays at the surface
   • BIce is denser than water and sinks
   • CHeat is conducted quickly up through the water
   • DThe bottom of the pond is cooled first

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6. Question 6· Thermal expansion· WAEC

   Ponds freeze from the top downwards because water is densest at

   • A4 °C
   • B0 °C
   • C100 °C
   • D−4 °C

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7. Question 7· Thermal expansion· WAEC

   The area expansivity of a solid is approximately

   • Atwice its linear expansivity
   • Bequal to its linear expansivity
   • Cthree times its linear expansivity
   • Dhalf its linear expansivity

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8. Question 8· Thermal expansion· WAEC

   Gaps are left between lengths of railway lines to allow for

   • Aexpansion in hot weather
   • Bdrainage of rainwater
   • Ceasy repair
   • Dnoise reduction

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   Explanation and discussion

9. Question 9· Thermal expansion· WAEC

   A metal rod 2 m long expands by 0.8 mm when heated through 20 K. Its linear expansivity is

   • A4 × 10⁻⁵ K⁻¹
   • B2 × 10⁻⁵ K⁻¹
   • C8 × 10⁻⁴ K⁻¹
   • D1 × 10⁻⁵ K⁻¹

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10. Question 10· Thermal expansion· WAEC

    Gaps are left between lengths of railway line in order to

    • Aallow for expansion in hot weather
    • Breduce noise
    • Csave steel
    • Ddrain rainwater

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    Explanation and discussion

11. Question 11· Thermal expansion· WAEC

    A bimetallic thermostat works because the two metals

    • Aexpand by different amounts when heated
    • Bhave the same expansivity
    • Care magnetic
    • Ddo not expand

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    Explanation and discussion