Light Part 3: MCQs (Q51–Q75)
💡 Light – MCQs for Class 8 Science
Part 3: Q51–Q75
Q51. The least deviated colour of light in a prism is:
A) Blue
B) Violet
C) Green
D) Red
✅ Correct Answer: D) Red
Explanation:
- D) ✔ Red bends the least because it has the longest wavelength.
- B) Violet bends the most.
- A, C) Deviate moderately.
Q52. The most deviated colour of light in a prism is:
A) Red
B) Yellow
C) Blue
D) Violet
✅ Correct Answer: D) Violet
Explanation:
- D) ✔ Violet bends the most due to shortest wavelength.
Q53. The defect of vision where a person cannot see both near and distant objects clearly is:
A) Myopia
B) Hypermetropia
C) Presbyopia
D) Cataract
✅ Correct Answer: C) Presbyopia
Explanation:
- C) ✔ Caused by weakening ciliary muscles in old age.
Q54. Which mirror is used by shopkeepers to keep an eye on customers?
A) Plane mirror
B) Convex mirror
C) Concave mirror
D) Cylindrical mirror
✅ Correct Answer: B) Convex mirror
Explanation:
- B) ✔ Convex mirrors cover a wide field of view.
Q55. The part of the eye responsible for colour vision is:
A) Rod cells
B) Cone cells
C) Retina
D) Iris
✅ Correct Answer: B) Cone cells
Explanation:
- B) ✔ Cone cells detect colours in bright light.
- A) Rods are for dim light, not colour.
Q56. The image formed by a plane mirror is:
A) Real, inverted, same size
B) Virtual, erect, same size
C) Real, erect, diminished
D) Virtual, inverted, magnified
✅ Correct Answer: B) Virtual, erect, same size
Explanation:
- B) ✔ Plane mirror always gives upright, virtual, same-size images.
Q57. Which lens is used to correct hypermetropia?
A) Convex lens
B) Concave lens
C) Plano lens
D) Cylindrical lens
✅ Correct Answer: A) Convex lens
Explanation:
- A) ✔ Convex lens converges rays → helps long-sighted people.
Q58. Which lens is used in a magnifying glass?
A) Convex lens
B) Concave lens
C) Plano-concave lens
D) Plane mirror
✅ Correct Answer: A) Convex lens
Explanation:
- A) ✔ Convex lens produces enlarged virtual images when object is within focal length.
Q59. Which device uses multiple reflections to create colourful patterns?
A) Periscope
B) Kaleidoscope
C) Microscope
D) Telescope
✅ Correct Answer: B) Kaleidoscope
Explanation:
- B) ✔ Uses angled mirrors and coloured glass to make patterns.
Q60. The splitting of white light by a prism is called:
A) Reflection
B) Refraction
C) Dispersion
D) Diffusion
✅ Correct Answer: C) Dispersion
Explanation:
- C) ✔ Prism separates white light into spectrum (VIBGYOR).
Q61. The eye defect caused by clouding of the eye lens is:
A) Myopia
B) Hypermetropia
C) Cataract
D) Presbyopia
✅ Correct Answer: C) Cataract
Explanation:
- C) ✔ Cataract → blurred vision due to cloudy lens.
Q62. The function of the iris in the human eye is to:
A) Form images
B) Adjust the size of pupil
C) Focus light
D) Carry signals to brain
✅ Correct Answer: B) Adjust the size of pupil
Explanation:
- B) ✔ Iris regulates amount of light entering the eye.
Q63. The part of the eye where an image is formed is:
A) Lens
B) Cornea
C) Retina
D) Iris
✅ Correct Answer: C) Retina
Explanation:
- C) ✔ Retina acts like a screen → forms real, inverted image.
Q64. Which mirror is used as a shaving mirror?
A) Convex mirror
B) Concave mirror
C) Plane mirror
D) Cylindrical mirror
✅ Correct Answer: B) Concave mirror
Explanation:
- B) ✔ Concave mirror magnifies face → used for shaving.
Q65. The defect of the eye that can be corrected by bifocal lenses is:
A) Cataract
B) Presbyopia
C) Myopia
D) Astigmatism
✅ Correct Answer: B) Presbyopia
Explanation:
- B) ✔ Presbyopia → bifocal lens corrects both near & far vision.
Q66. Which part of the human eye is a transparent layer at the front?
A) Retina
B) Cornea
C) Lens
D) Iris
✅ Correct Answer: B) Cornea
Explanation:
- B) ✔ Cornea covers pupil and helps refract light.
Q67. Which type of mirror is used in solar cookers?
A) Convex mirror
B) Concave mirror
C) Plane mirror
D) Cylindrical mirror
✅ Correct Answer: B) Concave mirror
Explanation:
- B) ✔ Concave mirrors focus sunlight at one point → cooking.
Q68. The eye defect caused due to weakening of ciliary muscles with age is:
A) Myopia
B) Hypermetropia
C) Presbyopia
D) Cataract
✅ Correct Answer: C) Presbyopia
Explanation:
- C) ✔ Ciliary muscles weaken → eye cannot focus properly.
Q69. Which lens is used in spectacles for myopia?
A) Convex lens
B) Concave lens
C) Bifocal lens
D) Plano lens
✅ Correct Answer: B) Concave lens
Explanation:
- B) ✔ Concave lens diverges rays → helps short-sighted eyes.
Q70. Which part of the human eye controls the amount of light entering?
A) Lens
B) Retina
C) Iris
D) Cornea
✅ Correct Answer: C) Iris
Explanation:
- C) ✔ Iris adjusts pupil size → controls light entry.
Q71. Which phenomenon explains why stars twinkle but planets do not?
A) Reflection
B) Atmospheric refraction
C) Dispersion
D) Scattering
✅ Correct Answer: B) Atmospheric refraction
Explanation:
- B) ✔ Starlight bends irregularly → twinkling, planets appear steady.
Q72. Which lens is used in the simple microscope?
A) Concave lens
B) Convex lens
C) Plane mirror
D) Concave mirror
✅ Correct Answer: B) Convex lens
Explanation:
- B) ✔ Convex lens magnifies objects when close.
Q73. The eye lens forms an image that is:
A) Real, inverted, smaller
B) Real, inverted, on retina
C) Virtual, erect
D) Virtual, magnified
✅ Correct Answer: B) Real, inverted, on retina
Explanation:
- B) ✔ Eye lens makes real inverted image on retina.
Q74. Which mirror is used in vehicle headlights?
A) Convex mirror
B) Concave mirror
C) Plane mirror
D) Cylindrical mirror
✅ Correct Answer: B) Concave mirror
Explanation:
- B) ✔ Concave mirror focuses light → strong beam in headlights.
Q75. Which phenomenon is responsible for the apparent bending of a stick in water?
A) Reflection
B) Refraction
C) Dispersion
D) Diffraction
✅ Correct Answer: B) Refraction
Explanation:
- B) ✔ Light bends at water-air boundary → stick appears bent.
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