WAEC Physics questions: Optical instruments

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

1. Question 1· Optical instruments· WAEC

   In a simple camera, the image is focused by

   • Achanging the aperture size
   • Bchanging the shutter speed
   • Cmoving the lens towards or away from the film
   • Dusing a mirror

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   Explanation and discussion

2. Question 2· Optical instruments· WAEC

   In a simple camera, the image is focused on the film by

   • Achanging the aperture
   • Bmoving the lens
   • Cchanging the shutter speed
   • Dmoving the film only by hand

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   Explanation and discussion

3. Question 3· Optical instruments· WAEC

   The image formed on the retina of the human eye is

   • Areal, inverted and diminished
   • Bvirtual and erect
   • Creal and erect
   • Dvirtual, inverted and magnified

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   Explanation and discussion

4. Question 4· Optical instruments· WAEC

   Find the power of a diverging lens of focal length 25 cm.

   • A−0.04 D
   • B+4 D
   • C−4 D
   • D+25 D

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5. Question 5· Optical instruments· WAEC

   Short sight is corrected using a

   • Aconverging lens
   • Bdiverging lens
   • Cplane mirror
   • Dprism

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6. Question 6· Optical instruments· WAEC

   An object is placed 20 cm from a converging lens of focal length 10 cm. The image is formed at a distance of

   • A20 cm
   • B10 cm
   • C6.7 cm
   • D30 cm

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7. Question 7· Optical instruments· WAEC

   Short-sightedness is corrected with a

   • Adiverging lens
   • Bconverging lens
   • Cplane mirror
   • Dprism

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   Explanation and discussion

8. Question 8· Optical instruments· WAEC

   A converging lens of focal length 5 cm is used as a magnifying glass with the final image at the near point, 25 cm away. Find the magnification.

   • A4
   • B5
   • C6
   • D25

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9. Question 9· Optical instruments· WAEC

   Prism binoculars use right-angled prisms mainly to

   • Aabsorb stray light
   • Bsplit light into colours
   • Cmagnify the image
   • Dinvert the image by total internal reflection

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10. Question 10· Optical instruments· WAEC

    The image formed on the screen by a slide projector is

    • Areal and diminished
    • Bvirtual and upright
    • Creal, inverted and magnified
    • Dvirtual and magnified

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    Explanation and discussion