JAMB and WAEC Physics questions: Light: refraction

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

1. Question 21· Light: refraction· WAEC

   A coin lies at the bottom of water 12 cm deep. If the refractive index of water is 4/3, how deep does the coin appear?

   • A16 cm
   • B9 cm
   • C3 cm
   • D12 cm

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   Explanation and discussion

2. Question 22· Light: refraction· WAEC

   Light passes from air into glass of refractive index 1.5 at an angle of incidence of 30°. Find the angle of refraction.

   • A19.5°
   • B30°
   • C48.6°
   • D45°

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   Explanation and discussion

3. Question 23· Light: refraction· WAEC

   Water has a refractive index of 1.33. Find the speed of light in water. (c = 3 × 10⁸ m/s)

   • A3.99 × 10⁸ m/s
   • B2.26 × 10⁸ m/s
   • C1.33 × 10⁸ m/s
   • D4.0 × 10⁸ m/s

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   Explanation and discussion

4. Question 24· Light: refraction· JAMB

   Find the speed of light in a medium of refractive index 1.33. (c = 3 × 10⁸ m/s)

   • A4.4 × 10⁸ m/s
   • B3.99 × 10⁸ m/s
   • C1.33 × 10⁸ m/s
   • D2.26 × 10⁸ m/s

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   Explanation and discussion

5. Question 25· Light: refraction· JAMB

   A mirage seen on a hot road is caused by

   • Adiffraction of light
   • Breflection from water on the road
   • Crefraction and total internal reflection in layers of hot air
   • Dabsorption by the road

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   Explanation and discussion

6. Question 26· Light: refraction· JAMB

   Find the critical angle for a medium of refractive index 2.

   • A60°
   • B30°
   • C45°
   • D90°

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   Explanation and discussion

7. Question 27· Light: refraction· JAMB

   Total internal reflection occurs when light goes from a denser to a less dense medium and the angle of incidence

   • Aexceeds the critical angle
   • Bis zero
   • Cis always 45°
   • Dis less than the critical angle

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   Explanation and discussion