Light Part 2: MCQs (Q26–Q50)
💡 Light – MCQs for Class 8 Science
Part 2: Q26–Q50
Q26. Which part of the human eye is sensitive to light?
A) Cornea
B) Retina
C) Iris
D) Lens
✅ Correct Answer: B) Retina
Explanation:
- B) ✔ Retina has rods and cones that sense light and colour.
- A, C, D are important but not directly responsible for light sensitivity.
Q27. The persistence of vision in the human eye is about:
A) 1/5 second
B) 1/16 second
C) 1 second
D) 1 minute
✅ Correct Answer: B) 1/16 second
Explanation:
- B) ✔ Eye retains an image for 1/16 of a second, allowing movies to appear continuous.
Q28. The phenomenon of light entering the eye through the pupil and forming an image on the retina is called:
A) Reflection
B) Refraction
C) Dispersion
D) Scattering
✅ Correct Answer: B) Refraction
Explanation:
- B) ✔ The convex eye lens refracts light to focus on the retina.
Q29. Which lens is used by a person suffering from hypermetropia?
A) Concave lens
B) Convex lens
C) Cylindrical lens
D) Plane mirror
✅ Correct Answer: B) Convex lens
Explanation:
- B) ✔ Convex lens converges rays → corrects long-sightedness.
Q30. Which part of the eye helps in changing the focal length of the eye lens?
A) Retina
B) Iris
C) Ciliary muscles
D) Cornea
✅ Correct Answer: C) Ciliary muscles
Explanation:
- C) ✔ Ciliary muscles adjust the shape of lens to focus on near/far objects.
Q31. The process by which the eye lens becomes thin or thick to focus objects is called:
A) Refraction
B) Accommodation
C) Persistence of vision
D) Dispersion
✅ Correct Answer: B) Accommodation
Explanation:
- B) ✔ Eye lens adjusts focal length to focus images → accommodation.
Q32. Which mirror always forms a virtual, erect, and diminished image?
A) Plane mirror
B) Concave mirror
C) Convex mirror
D) None
✅ Correct Answer: C) Convex mirror
Explanation:
- C) ✔ Convex mirrors give diminished, upright images → used as rear-view mirrors.
Q33. A concave mirror is used by dentists because:
A) It enlarges the image
B) It diminishes the image
C) It gives inverted images
D) It gives multiple reflections
✅ Correct Answer: A) It enlarges the image
Explanation:
- A) ✔ Concave mirrors magnify nearby objects, useful for examining teeth.
Q34. Which of the following is an example of refraction of light?
A) Echo
B) Twinkling of stars
C) Bending of pencil in water
D) Image in plane mirror
✅ Correct Answer: C) Bending of pencil in water
Explanation:
- C) ✔ Apparent bending due to refraction at water surface.
Q35. The speed of light is maximum in:
A) Air
B) Glass
C) Water
D) Vacuum
✅ Correct Answer: D) Vacuum
Explanation:
- D) ✔ Light travels fastest in vacuum, slower in denser media.
Q36. A rainbow is formed due to:
A) Reflection and refraction
B) Refraction, dispersion, and reflection
C) Diffraction and scattering
D) Absorption and transmission
✅ Correct Answer: B) Refraction, dispersion, and reflection
Explanation:
- B) ✔ Light is refracted, dispersed into colours, and internally reflected in water drops.
Q37. Which phenomenon explains the twinkling of stars?
A) Dispersion
B) Refraction through atmosphere
C) Scattering
D) Reflection
✅ Correct Answer: B) Refraction through atmosphere
Explanation:
- B) ✔ Starlight bends due to atmospheric refraction, causing twinkling.
Q38. Which of the following is a use of plane mirrors?
A) As shaving mirrors
B) In periscopes
C) As headlights
D) As rear-view mirrors
✅ Correct Answer: B) In periscopes
Explanation:
- B) ✔ Plane mirrors reflect light to form upright images in periscopes.
Q39. If the angle of incidence is 40°, what is the angle of reflection?
A) 20°
B) 30°
C) 40°
D) 60°
✅ Correct Answer: C) 40°
Explanation:
- C) ✔ Law of reflection → angle of incidence = angle of reflection.
Q40. A person cannot see nearby objects clearly. This defect is called:
A) Myopia
B) Hypermetropia
C) Presbyopia
D) Cataract
✅ Correct Answer: B) Hypermetropia
Explanation:
- B) ✔ Long-sightedness = cannot see near objects clearly.
Q41. Which part of the eye sends the visual signal to the brain?
A) Retina
B) Iris
C) Optic nerve
D) Cornea
✅ Correct Answer: C) Optic nerve
Explanation:
- C) ✔ Optic nerve carries signals from retina to brain.
Q42. The eye defect in old age where both near and far vision are affected is called:
A) Myopia
B) Hypermetropia
C) Presbyopia
D) Cataract
✅ Correct Answer: C) Presbyopia
Explanation:
- C) ✔ Presbyopia occurs due to weakening of ciliary muscles with age.
Q43. Which type of lens is used in spectacles for myopia?
A) Convex lens
B) Concave lens
C) Cylindrical lens
D) Plano-convex lens
✅ Correct Answer: B) Concave lens
Explanation:
- B) ✔ Diverging concave lens corrects short-sightedness.
Q44. The image formed on the retina is:
A) Virtual and erect
B) Real and inverted
C) Real and erect
D) Virtual and inverted
✅ Correct Answer: B) Real and inverted
Explanation:
- B) ✔ Eye lens forms a real, inverted image on retina.
Q45. The phenomenon due to which a coin in water appears raised is:
A) Reflection
B) Refraction
C) Scattering
D) Dispersion
✅ Correct Answer: B) Refraction
Explanation:
- B) ✔ Light bends at water-air interface → apparent shift.
Q46. Which mirror is used in torches?
A) Plane mirror
B) Convex mirror
C) Concave mirror
D) Cylindrical mirror
✅ Correct Answer: C) Concave mirror
Explanation:
- C) ✔ Concave mirror converges light into a parallel beam.
Q47. Which of the following is NOT an optical instrument?
A) Microscope
B) Telescope
C) Periscope
D) Seismograph
✅ Correct Answer: D) Seismograph
Explanation:
- D) ✔ Seismograph records earthquakes, not light.
Q48. What type of lens is used in magnifying glasses?
A) Concave lens
B) Convex lens
C) Cylindrical lens
D) Plane mirror
✅ Correct Answer: B) Convex lens
Explanation:
- B) ✔ Convex lens magnifies objects by forming enlarged virtual images.
Q49. Which of these mirrors can form both real and virtual images?
A) Plane mirror
B) Convex mirror
C) Concave mirror
D) None
✅ Correct Answer: C) Concave mirror
Explanation:
- C) ✔ Concave mirrors can form real (beyond focus) and virtual (within focus) images.
Q50. The front part of the eye covered by a transparent layer is called:
A) Lens
B) Cornea
C) Retina
D) Iris
✅ Correct Answer: B) Cornea
Explanation:
- B) ✔ Cornea is the transparent front part helping in refraction.
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