JAMB and WAEC Physics questions: Thermal expansion

23 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· JAMB

   A metal has a linear expansivity of 1.1 × 10⁻⁵ K⁻¹. Find its area expansivity.

   • A1.21 × 10⁻¹⁰ K⁻¹
   • B3.3 × 10⁻⁵ K⁻¹
   • C1.1 × 10⁻⁵ K⁻¹
   • D2.2 × 10⁻⁵ K⁻¹

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5. Question 5· Thermal expansion· JAMB

   Thermostats in electric irons usually use

   • Aa bimetallic strip
   • Ba mercury thermometer
   • Ca magnet
   • Da transformer

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   Explanation and discussion

6. Question 6· 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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7. Question 7· Thermal expansion· JAMB

   A metal rod 2 m long has a linear expansivity of 1.2 × 10⁻⁵ K⁻¹. Find its increase in length when heated through 50 K.

   • A2.4 × 10⁻³ m
   • B1.2 × 10⁻⁴ m
   • C1.2 × 10⁻³ m
   • D6 × 10⁻⁴ m

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8. Question 8· Thermal expansion· JAMB

   Water has its maximum density at

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

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9. Question 9· Thermal expansion· JAMB

   A rod 1 m long with linear expansivity 2 × 10⁻⁵ K⁻¹ is heated through 100 K. Find its increase in length.

   • A2 × 10⁻⁵ m
   • B2 × 10⁻³ m
   • C2 × 10⁻² m
   • D0.2 m

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10. Question 10· Thermal expansion· JAMB

    Overhead electric cables sag more in hot weather because they

    • Aexpand
    • Bcontract
    • Cbecome heavier
    • Dlose their charge

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    Explanation and discussion

11. Question 11· Thermal expansion· JAMB

    The cubic expansivity of a solid is approximately

    • Athree times its linear expansivity
    • Bequal to its linear expansivity
    • Ctwice its linear expansivity
    • Dhalf its linear expansivity

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12. Question 12· 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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13. Question 13· 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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    Explanation and discussion

14. Question 14· 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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15. Question 15· Thermal expansion· JAMB

    The anomalous expansion of water means that water

    • Afreezes at 4 °C
    • Bexpands uniformly
    • Cboils at 0 °C
    • Dcontracts when heated from 0 °C to 4 °C

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16. Question 16· 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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17. Question 17· Thermal expansion· JAMB

    The real expansion of a liquid in a container is equal to

    • Aits apparent expansion only
    • Bits apparent expansion minus the expansion of the container
    • Cthe expansion of the container only
    • Dits apparent expansion plus the expansion of the container

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18. Question 18· 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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19. Question 19· Thermal expansion· JAMB

    A bimetallic strip bends when heated because the two metals have different

    • Alinear expansivities
    • Bdensities
    • Cspecific heat capacities
    • Dmelting points

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20. Question 20· Thermal expansion· JAMB

    A bimetallic strip bends when heated because

    • Athe metals melt
    • Bboth metals contract
    • Cits two metals expand by different amounts
    • Dit becomes magnetised

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    Explanation and discussion