Geometrical Optics - MCQs, Fill in the blanks and Concept Map - Physics II - For Class X (Science Group)

Go To Index
Unit 13: Geometrical Optics
Physics II
For Class X (Science Group)

SECTION A
Multiple Choice Questions (MCQs)

Choose the corretc answer from the following choices:
1. In a concave mirror, the image size depends upon:
a) Size of the object
b) Position of the object ✔
c) Area covered by the object
d) The shape of the object

2. In the normal human eye, the image is formed:
a) In front of the retina
b) Behind the retina
c) On the retina ✔
d) In between lens and retina

3. When a light ray enters from a denser medium to a rare medium, it bends:
a) Perpendicular to nonnal
b) Parallel to normal
c) Toward normal
d) Away from normal ✔

4. In a compound microscope, as compared to an objective the eyepiece lens has a focal length:
a) Zero
b) Negative
c) Small
d) Large ✔

5. When the angle of refraction is 90° and there refractive index for water is 1.33, the critical angle is:
a) 48.8° ✔
b) 49.1°
c) 50.0°
d) 51.0°

6. To view dim stars, we use:
a) Compound microscope
b) Simple microscope
c) Endoscope
d) Telescope ✔

7. The human eye acts like a:
a) Camera ✔
b) Projector
c) Telescope
d) Microscope

8. A magnifying glass forms an enlarged:
a) Real and upright image
b) Real and inverted
c) Virtual and upright image ✔
d) Virtual and inverted image

9. The entire light is reflected into the same denser medium. Which is called total:
a) External reflection
b) Internal reflection ✔
c) External refraction
d) Internal refraction

10. In the optic fiber the core is made of glass or plastic of relatively:
a) Zero refractive index
b) High refractive index ✔
c) Low refractive index
d) refractive index

11. A magnifying glass is also called:
a) Endoscope
b) Compound microscope
c) Simple microscope ✔
d) Telescope

12. The defect in which the image is formed beyond the retina is called:
a) Long-sightedness ✔
b) Short-sightednest
c) Blind spotting
d) Image defect

13. The short-sightedness can be corrected by using:
a) Convex glasses ✔
b) Convex mirror
c) Concave mirror
d) Convex glasses

14. Lenses form images through:
a) Dispersion
b) Refraction ✔
c) Diffraction
d) Reflection

15. To illuminate the inaccessible places in the tooth, dentists use:
a) Concave mirror ✔
b) Convex mirror
c) Convex lens
d) Concave lens

More Multiple Choice Questions (MCQs)

16. Tick the correct mirror equation:
a) 1/p = 1/f + 1/q
b) 1/q = 1/f + 1/p
c) 1/f = 1/q + 1/p ✔
d) 1/f = 1/q - 1/p

17. Which statement is correct?
a) A concave mirror has a positive focal length, while a convex mirror has a negative focal length. ✔
b) A concave mirror has a negative focal length, while a convex mirror has a positive focal length.
c) A concave mirror and a convex mirror, both have negative focal lengths.
d) A concave mirror and a convex mirror, both have positive focal lengths.

18. They are often used as rear-view mirrors or wing mirrors in vehicles, also called driver mirrors.
a) Concave mirrors
b) Convex mirrors ✔
c) Concave lenses
d) Convex lenses

19. A ray of light perpendicular to the glass slab or along the normal is:
a) refracted
b) not refracted ✔
c) sometimes refracted
d) It depends on medium

20. A ray of light incident at an angle to the normal bends towards the normal when it enters into an optically:
a) denser medium ✔
b) less dense medium
c) glass to air
d) Both 'a' & 'c'

21. A ray of light bench away from the normal when it enters an optically:
a) less dense medium
b) glass to air
c) Both 'a' & 'b' ✔
d) None of them

22. The ratio of the sine angle of incidence to the sine angle of refraction gives us a constant called the:
a) angle of incidence
b) angle of reflection
c) angle of refraction
d) refractive index of the medium ✔

23. Refraction of light is caused by a change in speed, at the interface of two different mediums:
a) the wavelength of the ray changes while the frequency of light does not change ✔
b) frequency of the ray changes while the wavelength of light does not change
c) wavelength and frequency of the ray remain unchanged
d) Both, wavelength and frequency change

24. For refractive index:
a) n = c + v
b) n = cv
c) n = c/v ✔
d) n = v/c

25. Which one of these has the largest refractive index?
a) Ice
b) Diamond ✔
c) Glass
d) Water

26. The angle of incidence that causes the refracted ray in the rarer medium to bend through 90° is called the:
a) angle of incidence
b) angle of refraction
c) angle of reflection
d) critical angle ✔

27. An optical fiber comprises:
a) two parts ✔
b) three parts
c) four parts
d) five parts

28. The inner port 'core' of an optical fibre is coated with another material called "cladding" which has:
a) zero refractive index
b) high refractive index
c) low refractive index ✔
d) no refractive index

29. The reciprocal of a lens focal length is called:
a) refractive index
b) power of the lens ✔
c) critical angle
d) None of t them

30. The power of a lens is measured in:
a) meter
b) (meter)²
c) (meter)^-2
d) (meter)^-1 ✔

31. The SI unit of power of a lens is:
a) meter^-1
b) watts
c) diopter ✔
d) Hertz

32. 1 diopter = ________:
a) 1 meter^-1 ✔
b) 1 meter^-2
c) 1 meter
d) 1 meters²

33. Which statement is correct?
a) The power of a convex lens is negative, and that of a concave lens is positive.
b) The power of a convex lens is positive, and that of a concave lens is negative. ✔
c) The power of both lenses is positive
d) The power of both lenses is negative

34. The nature, position, and size of the image formed by a convex lens depend on the position of the object about point/s:
a) 2F
b) F
c) C
d) All of them ✔

35. Magnification = ?
a) size of image + size of object
b) size of image x size of object
c) size of image / size of object ✔
d) size of object / size of image

36. The magnification of a compound microscope is given by:
a) 1 + 25 cm/f ✔
b) 1 + f/25 cm
c) 1 - 25 cm/f
d) 1 - f/25 cm

37. Scientists believe that a human with a normal eye and regular vision can see the tiniest objects as small as about:
a) 0.1 mm ✔
b) 0.1 cm
c) 0.1 m
d) 0.1 μm

38. In a telescope, as compared to an eye piece, the objective lens has a focal length:
a) zero
b) negative
c) small
d) large ✔

39. The magnification of a telescope is given by the formula:
a) f_e / f_o
b) f_o / f_e ✔
c) 1 + f_e / f_o
d) 1 + f_o / f_e

40. The human eye uses a convex lens system to form a:
a) real, upright, a small image of an object
b) virtual, inverted a small image of an object
c) real, inverted, a small image of an object ✔
d) virtual, upright, a small image of an object

41. In this eye defect, the image of a distant object is formed in front of the retina and not at the retina itself:
a) Short-sightedness ✔
b) Long-sightedness
c) Hyperopia
d) Both 'a' & 'c'

42. The long-sightedness can be corrected by using:
a) convex glasses ✔
b) convex mirror
c) concave mirror
d) concave glasses

43. The size of the image is always smaller than the object in:
a) convex mirror ✔
b) concave mirror
c) silver mirror
d) plane mirror

44. For a diverging lens the focal length is:
a) positive
b) negative ✔
c) zero
d) constant

45. The quantity which does not change during refraction is:
a) direction
b) speed
c) frequency ✔
d) wavelength

46. One of the angles of a right-angled prism is:
a) 30°
b) 45°
c) 90° ✔
d) 60°

47. Concave lens is also called:
a) diverging lens ✔
b) converging lens
c) magnifying glass
d) none of above

48. Power of a lens is defined as the reciprocal of its:
a) focal length in meters ✔
b) principal axis
c) optical center
d) pole

49. The focus lies behind the mirror in:
a) convex mirror ✔
b) concave mirror
c) plane mirror
d) None of them

50. In a compound microscope, the focal length of the objective lens is:
a) short ✔
b) large
c) zero
d) None of above

51. A magnifying glass forms:
a) real image
b) inverted image
c) virtual image ✔
d) None of them

52. A spherical mirror whose inner curved surface is reflecting is called:
a) plane mirror
b) convex mirror
c) concave mirror ✔
d) All of them

53. A compound microscope uses:
a) 2 lenses ✔
b) 1 lens
c) 4 lenses
d) 5 lenses

54. The angle of reflection and the angle of reflection are:
a) both positive
b) not equal
c) equal ✔
d) opposite

55. The inner part of the fibre optics which carries light is called:
a) prism
b) cladding
c) core ✔
d) diopters

56. The convex lens becomes a magnifying glass when:
a) an object is placed inside the lens's focal length ✔
b) an object is placed at a focal length
c) an object is placed behind focal length
d) object is placed inverted in front of the lens

57. The ciliary muscles of the eye control the:
a) lens movement
b) lens curvature and focal length ✔
c) pupil
d) retina

58. When the angle of incidence becomes larger than the critical angle, then:
a) refraction occurs
b) reflection occurs
c) dispersion occurs
d) no refraction occurs ✔

59. The outer concentric shell of the fibre optics is called:
a) diopters
b) core
c) prism
d) cladding ✔

60. The ability to distinguish between two closely placed objects or point sources is called an instrument:
a) reflecting power
b) resolving power ✔
c) optical power
d) refractive index

61. In the photograph enlarger, the object is placed:
a) between F and 2F ✔
b) beyond 2F
c) at F
d) less than F

62. The angle of incidence that causes the refracted ray to bend through 90° is called:
a) acute angle
b) obtuse angle
c) right angle
d) critical angle ✔

63. In the camera the distance between lens and film is fixed and is equal to:
a) p
b) q
c) focal length ✔
d) principal axis

FILL IN THE BLANKS

• A highly polished surface reflects the light.
• The incident ray, reflected ray, and the normal to the reflecting surface all lie in the same plane. This phenomenon is called the first law of reflection.
• The angle of incidence is equal to the angle of reflection (i.e., ∠i = ∠r). This is the second law of reflection.
• Some uses of a convex mirror are sunglasses, rearview mirrors, and shaving mirrors.
• Some applications of concave mirrors are reflectors, converging of light, and solar cookers.
• The driver uses concave or rearview mirrors to view an upright, smaller, and full vehicle image.
• The dentist uses a concave mirror to see the tooth is larger and if there is any infection or germ attack.
• A ray of light incident at an angle to the normal bends towards the normal when it enters an optically denser medium.
• A ray of light bends away from the normal when it enters a rear medium.
• The angle of incidence that causes the refracted ray in the rarer medium to bend through 90° is called the critical angle.
• If the angle of incidence in the denser material is beyond the critical angle, the entire light is reflected into the same denser medium is called total internal reflection.
• Optical fibers are an important application that works on total internal reflection.
• Convex lenses are used to converge the light.
• Concave lenses are used to diverge the light.
• The power of a lens is the reciprocal of its focal length.
• The magnifying glass uses a convex lens to produce an upright and magnified image to see the tiny object.
• The camera uses a convex lens to reproduce a small, inverted, and small image on photographic film.
• The projector uses a convex lens as a projection lens and pair of condenser lenses to produce a large, inverted, and real image on a screen
• The photographic enlarger uses a convex lens to produce an inverted, real and enlarged image of the film on a photo paper.
• The resolving power of an optical instrument is a measure of the ability to form separable images of close objects or to separate close wavelengths of radiation.
• The magnifying power of an optical instrument is the ratio between the apparent size of an object and its true size.
• The compound microscope is an optical instrument that uses two convex lenses, used to investigate the structure of the tiniest objects.
• The telescope is also an optical instrument that is used to form magnified images of distant objects.
• The human eye is a light-sensitive sense organ.
• The short-sight person can see nearby objects clearly but cannot see distant objects distinctly.
• The short-sight defect can be corrected by placing a concave lens or contact of appropriate power in front of the eye.
• The long-sight person can see distant objects clearly but cannot see nearby objects distinctly.
• The long-sight defect can be corrected by placing a convex lens or contact of appropriate power in front of the eye.

CONCEPT MAP