JAMB and WAEC Physics questions: Light: refraction

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

1. Question 1· Light: refraction· WAEC

   The critical angle for glass of refractive index 1.5 is about

   • A90°
   • B30°
   • C60°
   • D42°

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   Explanation and discussion

2. Question 2· Light: refraction· JAMB

   A pool is 20 cm deep. Find its apparent depth when viewed from above. (Refractive index of water = 1.33)

   • Aabout 10 cm
   • Babout 27 cm
   • C20 cm
   • Dabout 15 cm

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   Explanation and discussion

3. Question 3· Light: refraction· JAMB

   Optical fibres carry light by

   • Ainterference
   • Bdiffraction
   • Ctotal internal reflection
   • Dpolarisation

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   Explanation and discussion

4. Question 4· Light: refraction· JAMB

   A coin lies at the bottom of a tank of water 12 cm deep. Find its apparent depth. (Refractive index of water = 4/3)

   • A9 cm
   • B16 cm
   • C12 cm
   • D8 cm

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5. Question 5· Light: refraction· JAMB

   An object is placed 30 cm from a converging lens of focal length 10 cm. The image distance is:

   • A7.5 cm
   • B15 cm
   • C20 cm
   • D40 cm

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   Explanation and discussion

6. Question 6· Light: refraction· WAEC

   A ray of light passing from air into glass bends

   • Aback into the air
   • Baway from the normal
   • Calong the surface
   • Dtowards the normal

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   Explanation and discussion

7. Question 7· Light: refraction· WAEC

   A coin at the bottom of water 4 m deep appears 3 m deep. The refractive index of the water is

   • A0.75
   • B1.33
   • C1.5
   • D7

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8. Question 8· Light: refraction· JAMB

   A ray in air strikes a glass surface at an angle of incidence of 60° and is refracted at 30°. Find the refractive index of the glass.

   • A√2
   • B2
   • C1/√3
   • D√3

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9. Question 9· Light: refraction· JAMB

   

   A ray passes from air into a glass block as shown. Given that sin 60° = 0.866 and sin 35° = 0.574, find the refractive index of the glass.

   • A1.71
   • B1.51
   • C0.66
   • D1.25

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   Explanation and discussion

10. Question 10· Light: refraction· JAMB

    Find the critical angle for glass of refractive index 1.5.

    • A41.8°
    • B48.2°
    • C30°
    • D60°

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    Explanation and discussion

11. Question 11· Light: refraction· JAMB

    Optical fibres carry light along their length by

    • Atotal internal reflection
    • Bdiffraction
    • Cdispersion
    • Dabsorption

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    Explanation and discussion

12. Question 12· Light: refraction· WAEC

    A swimming pool looks shallower than it really is because of

    • Adispersion
    • Breflection
    • Cdiffraction
    • Drefraction

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    Explanation and discussion

13. Question 13· Light: refraction· WAEC

    Light passes from air into glass of refractive index 1.5. If the angle of incidence is 30°, the sine of the angle of refraction is

    • A1.5
    • B0.75
    • C0.5
    • D1/3

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    Explanation and discussion

14. Question 14· Light: refraction· JAMB

    When light passes from air into glass, it

    • Adoes not bend
    • Bbends away from the normal
    • Cbends towards the normal
    • Dis totally reflected

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15. Question 15· Light: refraction· WAEC

    The power of a lens of focal length 25 cm is

    • A2.5 D
    • B0.04 D
    • C25 D
    • D4 D

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16. Question 16· Light: refraction· JAMB

    Find the speed of light in glass of refractive index 1.5. [c = 3 × 10⁸ m/s]

    • A3 × 10⁸ m/s
    • B4.5 × 10⁸ m/s
    • C2 × 10⁸ m/s
    • D1.5 × 10⁸ m/s

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17. Question 17· Light: refraction· WAEC

    The bending of light as it passes from one medium into another is

    • Areflection
    • Bdiffraction
    • Crefraction
    • Ddispersion

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18. Question 18· Light: refraction· WAEC

    A converging lens of focal length 10 cm forms an image of an object placed 15 cm from it at

    • A25 cm
    • B6 cm
    • C30 cm
    • D10 cm

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19. Question 19· Light: refraction· WAEC

    Find the critical angle for water of refractive index 4/3.

    • A36.9°
    • B41.8°
    • C48.6°
    • D53.1°

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20. Question 20· Light: refraction· JAMB

    The refractive index of glass is 1.5. The speed of light in the glass is: (c = 3 × 10⁸ m/s)

    • A1.5 × 10⁸ m/s
    • B3 × 10⁸ m/s
    • C4.5 × 10⁸ m/s
    • D2 × 10⁸ m/s

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    Explanation and discussion