1. The angle of incidence is equal to the angle of reflection when light is reflected from a plane mirror. This is known as:
(A) Law of refraction
(B) Law of reflection
(C) Law of dispersion
(D) Law of diffraction
Answer: (B) Law of reflection
Explanation: According to the law of reflection, the angle of incidence equals the angle of reflection, both measured from the normal.
2. If the angle of incidence of a light ray is 40°, the angle of reflection will be:
(A) 20°
(B) 40°
(C) 80°
(D) 90°
Answer: (B) 40°
3. A rear-view mirror in automobiles is generally:
(A) Plane mirror
(B) Concave mirror
(C) Convex mirror
(D) Cylindrical mirror
Answer: (C) Convex mirror
Explanation: A convex mirror provides a wider field of view and forms an erect, diminished image.
4. Convex mirrors are used as rear-view mirrors because they:
(A) Produce magnified images
(B) Provide a wider field of view
(C) Produce inverted images
(D) Absorb more light
Answer: (B) Provide a wider field of view
5. Side-view mirrors of vehicles are generally:
(A) Concave mirrors
(B) Convex mirrors
(C) Plane mirrors
(D) Cylindrical lenses
Answer: (B) Convex mirrors
6. A convex mirror always forms an image that is:
(A) Real, inverted and enlarged
(B) Virtual, erect and diminished
(C) Real, erect and enlarged
(D) Virtual, inverted and enlarged
Answer: (B) Virtual, erect and diminished
7. A dentist uses a concave mirror because it can:
(A) Produce a magnified image of nearby objects
(B) Produce only diminished images
(C) Produce no image
(D) Provide a wider field of view
Answer: (A) Produce a magnified image of nearby objects
8. A dentist’s mirror is generally:
(A) Convex
(B) Concave
(C) Plane
(D) Cylindrical
Answer: (B) Concave mirror
9. A shaving mirror is generally concave because it:
(A) Produces a magnified upright image when the face is close to it
(B) Produces a diminished image
(C) Provides a wide field of view
(D) Always produces a real image
Answer: (A) Produces a magnified upright image when the face is close to it
10. Which type of mirror is used in a solar furnace to concentrate sunlight?
(A) Plane mirror
(B) Convex mirror
(C) Concave mirror
(D) Cylindrical mirror
Answer: (C) Concave mirror
11. A concave mirror is used in a solar furnace because it:
(A) Spreads sunlight over a large area
(B) Converges sunlight at a point or small region
(C) Absorbs sunlight completely
(D) Reflects sunlight backward
Answer: (B) Converges sunlight at a point or small region
12. Vehicle headlights commonly use a:
(A) Convex reflector
(B) Concave reflector
(C) Plane reflector only
(D) Concave lens
Answer: (B) Concave reflector
13. The main purpose of the concave reflector in a vehicle headlight is to:
(A) Scatter light in all directions
(B) Produce a strong, nearly parallel beam of light
(C) Absorb light
(D) Reduce the intensity of light
Answer: (B) Produce a strong, nearly parallel beam of light
14. A periscope works mainly on the principle of:
(A) Refraction
(B) Reflection of light
(C) Dispersion
(D) Diffraction
Answer: (B) Reflection of light
15. In a simple periscope, two plane mirrors are generally placed:
(A) At 45° to the incident direction
(B) At 90° to each other
(C) Parallel to the light direction
(D) At 10° to each other
Answer: (A) At 45° to the incident direction
16. A periscope allows a person to:
(A) See objects that are not directly in the line of sight
(B) See only nearby objects
(C) Magnify distant objects greatly
(D) Measure the speed of light
Answer: (A) See objects that are not directly in the line of sight
17. A kaleidoscope produces beautiful patterns mainly due to:
(A) Multiple reflection of light
(B) Refraction only
(C) Dispersion only
(D) Absorption of light
Answer: (A) Multiple reflection of light
18. The mirrors inside a kaleidoscope produce:
(A) Multiple images
(B) Only one image
(C) No image
(D) Only inverted images
Answer: (A) Multiple images
19. A rainbow is produced mainly due to:
(A) Reflection only
(B) Dispersion, refraction and internal reflection of sunlight
(C) Absorption only
(D) Diffraction only
Answer: (B) Dispersion, refraction and internal reflection of sunlight
20. The splitting of white light into its constituent colours is called:
(A) Reflection
(B) Dispersion
(C) Refraction
(D) Diffraction
Answer: (B) Dispersion
21. The seven colours of a rainbow are produced because white light:
(A) Is completely absorbed by raindrops
(B) Undergoes dispersion in water droplets
(C) Undergoes only reflection
(D) Becomes monochromatic
Answer: (B) Undergoes dispersion in water droplets
22. A rainbow is normally seen when sunlight interacts with:
(A) Dust particles only
(B) Water droplets in the atmosphere
(C) Smoke particles only
(D) Ice crystals only
Answer: (B) Water droplets in the atmosphere
23. A mirage seen on a hot road is mainly associated with:
(A) Refraction of light through layers of air of different temperatures
(B) Dispersion of light
(C) Reflection from a plane mirror
(D) Absorption of light
Answer: (A) Refraction of light through layers of air of different temperatures
24. The apparent appearance of water on a hot road when there is actually no water is an example of:
(A) Mirage
(B) Rainbow
(C) Halo
(D) Eclipse
Answer: (A) Mirage
25. A mirage is associated with:
(A) Refraction and, under suitable conditions, total internal reflection
(B) Dispersion only
(C) Diffraction only
(D) Polarization only
Answer: (A) Refraction and, under suitable conditions, total internal reflection
26. Optical fibres transmit light mainly through:
(A) Refraction
(B) Total internal reflection
(C) Dispersion
(D) Scattering
Answer: (B) Total internal reflection
27. Optical fibre communication is possible because light:
(A) Is completely absorbed inside the fibre
(B) Undergoes repeated total internal reflection
(C) Travels only through vacuum
(D) Is converted into sound
Answer: (B) Undergoes repeated total internal reflection
28. Which of the following is an important application of total internal reflection?
(A) Optical fibre
(B) Plane mirror
(C) Solar cell
(D) Electric motor
Answer: (A) Optical fibre
29. Diamonds shine brilliantly mainly because of:
(A) Total internal reflection
(B) Diffraction
(C) Absorption
(D) Polarization only
Answer: (A) Total internal reflection
30. The brilliance of a diamond is enhanced by cutting it into many facets because the facets:
(A) Increase absorption of light
(B) Allow repeated internal reflection of light
(C) Prevent refraction
(D) Convert light into heat
Answer: (B) Allow repeated internal reflection of light
31. A magnifying glass is generally a:
(A) Concave lens
(B) Convex lens
(C) Plane mirror
(D) Concave mirror
Answer: (B) Convex lens
32. A convex lens is used as a magnifying glass because it can produce:
(A) A magnified virtual image of an object placed within its focal length
(B) Only a diminished image
(C) Only a real image
(D) No image
Answer: (A) A magnified virtual image of an object placed within its focal length
33. The lens used in an ordinary camera is generally:
(A) Concave lens
(B) Convex lens
(C) Cylindrical lens
(D) Plane glass only
Answer: (B) Convex lens
34. The main function of the convex lens in a camera is to:
(A) Form a real image on the image sensor/film
(B) Produce only virtual images
(C) Scatter incoming light
(D) Absorb all incoming light
Answer: (A) Form a real image on the image sensor/film
35. A projector generally uses a:
(A) Convex lens
(B) Concave lens
(C) Plane mirror only
(D) Convex mirror
Answer: (A) Convex lens
36. A projector produces a large image on a screen using:
(A) A converging convex lens
(B) A diverging concave lens only
(C) A plane mirror only
(D) A convex mirror
Answer: (A) A converging convex lens
37. A compound microscope uses:
(A) Only plane mirrors
(B) Two or more convex lenses
(C) Only concave lenses
(D) Only convex mirrors
Answer: (B) Two or more convex lenses
38. The main purpose of a microscope is to:
(A) Produce a magnified image of a very small object
(B) Produce a diminished image
(C) Measure temperature
(D) Measure sound frequency
Answer: (A) Produce a magnified image of a very small object
39. A telescope is primarily used to:
(A) Observe distant objects
(B) Observe only microscopic objects
(C) Measure atmospheric pressure
(D) Produce sound
Answer: (A) Observe distant objects
40. Telescopes may use:
(A) Only concave lenses
(B) Lenses or mirrors, depending on the type
(C) Only plane mirrors
(D) Only cylindrical lenses
Answer: (B) Lenses or mirrors, depending on the type
41. The lens present in the human eye is approximately:
(A) Convex
(B) Concave
(C) Plane
(D) Cylindrical only
Answer: (A) Convex
42. The human eye forms an image on the:
(A) Cornea
(B) Retina
(C) Iris
(D) Pupil
Answer: (B) Retina
43. Myopia is commonly known as:
(A) Long-sightedness
(B) Short-sightedness
(C) Colour blindness
(D) Night blindness
Answer: (B) Short-sightedness
44. Myopia is corrected using a:
(A) Convex lens
(B) Concave lens
(C) Cylindrical lens only
(D) Plane glass
Answer: (B) Concave lens
45. A person suffering from myopia can see:
(A) Near objects clearly but distant objects poorly
(B) Distant objects clearly but nearby objects poorly
(C) Neither near nor distant objects
(D) Only objects behind the eye
Answer: (A) Near objects clearly but distant objects poorly
46. Hypermetropia is commonly known as:
(A) Short-sightedness
(B) Long-sightedness
(C) Colour blindness
(D) Night blindness
Answer: (B) Long-sightedness
47. Hypermetropia is corrected using a:
(A) Concave lens
(B) Convex lens
(C) Plane mirror
(D) Cylindrical mirror
Answer: (B) Convex lens
48. A person suffering from hypermetropia generally has difficulty seeing:
(A) Distant objects
(B) Nearby objects
(C) Very bright objects only
(D) Moving objects only
Answer: (B) Nearby objects
49. Astigmatism is commonly corrected using a:
(A) Concave lens
(B) Convex lens
(C) Cylindrical lens
(D) Plane mirror
Answer: (C) Cylindrical lens
50. Which of the following is correctly matched?
(A) Rear-view mirror — Convex mirror
(B) Dentist’s mirror — Convex mirror
(C) Myopia — Convex lens
(D) Hypermetropia — Concave lens
Answer: (A) Rear-view mirror — Convex mirror
51. Which of the following is incorrectly matched?
(A) Solar furnace — Concave mirror
(B) Optical fibre — Total internal reflection
(C) Magnifying glass — Convex lens
(D) Myopia — Convex lens
Answer: (D) Myopia — Convex lens
52. Which optical device is most directly associated with multiple reflection?
(A) Kaleidoscope
(B) Magnifying glass
(C) Camera
(D) Human eye
Answer: (A) Kaleidoscope
53. Which phenomenon is responsible for the formation of a rainbow?
(A) Reflection alone
(B) Dispersion, refraction and internal reflection
(C) Total internal reflection alone
(D) Diffraction alone
Answer: (B) Dispersion, refraction and internal reflection
54. Which of the following applications is based on total internal reflection?
(A) Optical fibre
(B) Rear-view mirror
(C) Magnifying glass
(D) Camera
Answer: (A) Optical fibre
55. Which pair is correctly matched?
(A) Periscope — Reflection
(B) Rainbow — Absorption
(C) Optical fibre — Diffraction
(D) Shaving mirror — Convex mirror
Answer: (A) Periscope — Reflection
56. Which of the following is used to obtain a wider field of view?
(A) Concave mirror
(B) Convex mirror
(C) Concave lens only
(D) Plane mirror only
Answer: (B) Convex mirror
57. Which combination is correctly matched with the type of lens used for correcting vision?
(A) Myopia — Concave lens; Hypermetropia — Convex lens
(B) Myopia — Convex lens; Hypermetropia — Concave lens
(C) Myopia — Cylindrical lens; Hypermetropia — Plane glass
(D) Myopia — Convex mirror; Hypermetropia — Concave mirror
Answer: (A) Myopia — Concave lens; Hypermetropia — Convex lens
58. If the angle of incidence of a ray falling on a plane mirror is 40°, the angle between the incident ray and reflected ray is:
(A) 40°
(B) 80°
(C) 50°
(D) 90°
Answer: (B) 80°
Explanation: Angle of reflection = 40°. Therefore, angle between incident and reflected rays = 40° + 40° = 80°.
59. The angle of incidence is measured between:
(A) Incident ray and mirror
(B) Incident ray and normal
(C) Reflected ray and mirror
(D) Normal and mirror
Answer: (B) Incident ray and normal
60. Which of the following contains the correct application-principle combination?
(A) Rear-view mirror — Convex mirror
(B) Dentist’s mirror — Concave mirror
(C) Optical fibre — Total internal reflection
(D) All of the above
Answer: (D) All of the above
Quick Revision — Light & Optics
| Application | Principle |
|---|---|
| Plane mirror | Reflection |
| Rear-view mirror | Convex mirror |
| Side-view mirror | Convex mirror |
| Dentist’s mirror | Concave mirror |
| Shaving mirror | Concave mirror |
| Solar furnace | Concave mirror |
| Vehicle headlights | Concave reflector |
| Periscope | Reflection |
| Kaleidoscope | Multiple reflection |
| Rainbow | Dispersion + refraction + internal reflection |
| Mirage | Refraction + total internal reflection |
| Optical fibre | Total internal reflection |
| Diamond | Total internal reflection |
| Magnifying glass | Convex lens |
| Camera | Convex lens |
| Projector | Convex lens |
| Microscope | Convex lenses |
| Telescope | Lenses/mirrors |
| Human eye | Convex lens |
| Myopia | Concave lens |
| Hypermetropia | Convex lens |
| Astigmatism | Cylindrical lens |
Must-Remember Exam Associations
Rear-view mirror → Convex
Dentist/shaving mirror → Concave
Solar furnace → Concave
Headlight reflector → Concave
Periscope → Reflection
Kaleidoscope → Multiple reflection
Rainbow → Dispersion + refraction + internal reflection
Optical fibre → Total internal reflection
Diamond → Total internal reflection
Magnifying glass → Convex lens
Camera → Convex lens
Projector → Convex lens
Myopia → Concave lens
Hypermetropia → Convex lens
Astigmatism → Cylindrical lens