WAEC Physics questions

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

1. Question 341· 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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   Answer: C. the inner surface expands more than the outer surface

   Explanation and discussion

2. Question 342· 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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   Answer: D. allow for expansion in hot weather

   Explanation and discussion

3. Question 343· 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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   Answer: B. 1.2 × 10⁻³ m

   Explanation and discussion

4. Question 344· 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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   Answer: A. from the top downwards, so fish survive below

   Explanation and discussion

5. Question 345· 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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   Answer: A. Water below 4 °C is less dense and stays at the surface

   Explanation and discussion

6. Question 346· 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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   Answer: A. 4 °C

   Explanation and discussion

7. Question 347· 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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   Answer: A. twice its linear expansivity

   Explanation and discussion

8. Question 348· 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

   Show answer

   Answer: A. expansion in hot weather

   Explanation and discussion

9. Question 349· 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

   Show answer

   Answer: B. 2 × 10⁻⁵ K⁻¹

   Explanation and discussion

10. Question 350· 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

    Show answer

    Answer: A. allow for expansion in hot weather

    Explanation and discussion

11. Question 351· 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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    Answer: A. expand by different amounts when heated

    Explanation and discussion

12. Question 352· Waves· WAEC

    Which of these is a longitudinal wave?

    • ALight wave
    • BRadio wave
    • CSound wave
    • DWater ripple

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    Answer: C. Sound wave

    Explanation and discussion

13. Question 353· Waves· WAEC

    A sound wave of frequency 500 Hz has a wavelength of 0.68 m. Find its speed.

    • A500 m/s
    • B735 m/s
    • C0.00136 m/s
    • D340 m/s

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    Answer: D. 340 m/s

    Explanation and discussion

14. Question 354· Waves· WAEC

    In a transverse wave the particles of the medium vibrate

    • Anot at all
    • Bparallel to the direction of travel
    • Cin circles only
    • Dperpendicular to the direction of travel

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    Answer: D. perpendicular to the direction of travel

    Explanation and discussion

15. Question 355· Waves· WAEC

    Find the period of a wave whose frequency is 25 Hz.

    • A0.4 s
    • B25 s
    • C0.04 s
    • D4 s

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    Answer: C. 0.04 s

    Explanation and discussion

16. Question 356· Waves· WAEC

    A radio station broadcasts at 100 MHz. If radio waves travel at 3 × 10⁸ m/s, find the wavelength.

    • A0.33 m
    • B3 m
    • C30 m
    • D3 × 10¹⁶ m

    Show answer

    Answer: B. 3 m

    Explanation and discussion

17. Question 357· Waves· WAEC

    Which electromagnetic radiation has the shortest wavelength?

    • Agamma rays
    • Bradio waves
    • Cinfrared
    • Dvisible light

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    Answer: A. gamma rays

    Explanation and discussion

18. Question 358· Waves· WAEC

    The number of complete oscillations made in one second is the

    • Afrequency
    • Bperiod
    • Camplitude
    • Dwavelength

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    Answer: A. frequency

    Explanation and discussion

19. Question 359· Waves· WAEC

    A radio station broadcasts at 100 MHz. The wavelength of its waves (c = 3 × 10⁸ m/s) is

    • A300 m
    • B30 m
    • C0.3 m
    • D3 m

    Show answer

    Answer: D. 3 m

    Explanation and discussion

20. Question 360· Waves· WAEC

    Diffraction is most noticeable when the gap size is

    • Aabout equal to the wavelength
    • Bmuch larger than the wavelength
    • Czero
    • Dvery large

    Show answer

    Answer: A. about equal to the wavelength

    Explanation and discussion