JAMB Physics questions: Light: refraction

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

1. Question 1· 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

2. Question 2· Light: refraction· JAMB

   Optical fibres carry light by

   • Ainterference
   • Bdiffraction
   • Ctotal internal reflection
   • Dpolarisation

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   Explanation and discussion

3. Question 3· 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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4. Question 4· 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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5. Question 5· 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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6. Question 6· 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

7. Question 7· Light: refraction· JAMB

   Find the critical angle for glass of refractive index 1.5.

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

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8. Question 8· Light: refraction· JAMB

   Optical fibres carry light along their length by

   • Atotal internal reflection
   • Bdiffraction
   • Cdispersion
   • Dabsorption

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9. Question 9· 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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10. Question 10· 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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11. Question 11· 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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12. Question 12· 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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13. Question 13· 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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14. Question 14· Light: refraction· JAMB

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

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

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15. Question 15· 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