Objective

Objective Questions and Answers

Reflection of Light

Question-1. What is a group of rays called?

Ans- beam

Question-2. What are the rays emanating from a point called?

Ans- divergent beam

Question-3. What are the rays going towards a point called?

Ans- convergent beam

Question-4. What are the rays moving parallel to each other called?

Ans- parallel beam

Question-5. What is the phenomenon of light hitting an object and returning it called?

Ans- reflection of light

Question-6. What is the phenomenon of bending of a ray of light at the interface of two transparent medium called?

Ans- Refraction of light

Question-7. What is the path on which light travels called?

Ans- beam

Question-8. Are the angle of incidence and angle of reflection equal to each other?

Ans- equal to (∠i = ∠r)

Question-9. The incident ray, the reflected ray and the normal drawn at the point of incidence are all three.

Ans- all three on the same floor

Question-10. How many types of images are there?

Ans- two

Question-11. The image formed by the actual cutting of the reflected or refracted light rays is called.

Ans- real image

Question-12. Reflected or refracted light-rays are brought back (by imaginary cutting) where they meet, that image is called.

Ans- imaginary reflection

Question-13. What are the real image and imaginary image compared to the object?

Ans-

real image → inverted

imaginary image → erect

Question-14. Which image can be found on the screen?

Ans- to the actual image

Question-15. Which image cannot be found on the screen?

Ans- to imaginary reflection

Question-16. The surface on which most of the incident light energy is reflected regularly is called

Ans- Mirror

Question-17. How many types of mirrors are there?

Ans- two (plane mirror and spherical mirror)

Question-18. On which mirror the rays of light falling vertically return on the same path after reflection. The rays of light falling vertically on which mirror return on the same path after reflection

Ans- on a plane mirror

Question-19. A plane mirror is used.

Ans- in the face-view mirror and in the solar cooker

Question-20. What is the image formed by a plane mirror?

Ans- erect, imaginary (virtual) and equal to the size of the object

Question-21. How many types of spherical mirrors are there?

Ans- two (concave mirror and convex mirror)

Question-22. The sphere of which the spherical (concave and convex) mirror is a part, what is the center of that sphere and its radius called?

Ans-

The center of the sphere is called → center of curvature (C) of the mirror.

The radius of the sphere is called → radius of curvature (R).

Question-23. The straight line joining the pole (P) and the center of curvature (C) of a spherical mirror is called.

Ans- Main axis

Question-24. What rules do spherical mirrors follow?

Ans- Laws of reflection of light

Question-25. The rays coming near the pole and at small angle of incidence are called

Ans- coaxial beam

Question-26. What is the distance of the principal-focus from the pole of a spherical mirror called?

Ans- focus-distance or focal length

Question-28. What is mirror formula?

Ans- 1/v + 1/u = 1/f

(v=image distance, u=object distance, f=focus distance)

Question-29. In a concave mirror, the focal length (f) and the radius of curvature (R) have a value.

Ans- negative

Question-30. In a convex mirror, the focal length (f) and the radius of curvature (R) have a value.

Ans- positive

Question-31. What is the image formed by a concave mirror?

Ans- both real and virtual and vice versa

Question-32. How is the image formed by a convex mirror of an object?

Ans- virtual (imaginary), upright and small

Question-33. What is the formula for magnification (m) of a spherical mirror?

Ans- m= h'/h and m= -v/u

[h' = image size (height), h = object size (height)]

Question-34. Which mirror is used for shaving, searchlight, torch, headlights of vehicles and for examining teeth, ears?

Ans- concave mirror

Question-35. Which mirror is used as rear view mirror of vehicles?

Ans- convex mirror

Question-36. Where is the image of an object placed at infinity formed in a concave mirror and what is the shape of the object?

Ans- The image of the object is formed at the principal-focus (F) of the mirror and the size of the object is real, inverted and much smaller than the size of the object.

Question-37. Where is the image of an object placed (far) beyond the center of curvature (C) of a concave mirror formed and what is the shape of the object?

Ans- The image of the object is formed between the principal focus (F) and the center of curvature (C) and the size of the object is real, inverted and smaller than the size of the object.

Question-38. Where is the image of an object placed at the center of curvature (C) formed in a concave mirror and what is the shape of the object?

Ans- The image of the object is formed at the center of curvature and the size of the object is real, inverted and equal to the size of the object.

Question-39. Where is the image of an object placed between the center of curvature (C) and principal focus (F) of a concave mirror formed and what is the shape of the object?

Ans- The image of the object is formed beyond the center of curvature and the size of the object is real, inverted and larger than the size of the object.

Question-40. Where is the image of an object placed at the principal-focus (F) of a concave mirror formed and what is the shape of the object?

Ans- The image of the object is formed at infinity and the size of the object is real, inverted and much larger than the size of the object.

Question-41. Where is the image of an object placed between the pole and principal-focus (F) of a concave mirror formed and what is the shape of the object?

Ans- The image of the object is formed behind the mirror and the size of the object is virtual (imaginary), erect and larger than the size of the object.

Question-42. Where is the object placed in the new Cartesian sign convention?

Ans- always to the left of the mirror

Question-43. In the new Cartesian sign convention, all distances are measured parallel to the principal axis.

Ans- from the mirror pole

Question-44. How are distances measured along the positive x-axis and distances measured along the negative x-axis in the new Cartesian sign convention?

Ans-

Distances measured towards the positive x-axis → धनात्मक

Distances Measured Towards the Negative X-Axis → ऋणात्मक

Question-45. In a convex mirror, if the object is placed between pole and infinity, where is the image formed?

Ans- The image of the object is formed between the pole of the mirror and the principal-focus (F).

Question-46. Where is the image of the object formed in a convex mirror if the object is placed at infinity?

Ans- The image of the object is formed at the principal-focus (F) of the mirror.

Question-47. Light rays travel through a transparent medium.

Ans- in a straight line

Question-48. speed of light in vacuum—

Ans- 3 × 10⁸ m/sec

Question-49. The real image is magnified.

Ans- negative

Question-50. The magnification of the virtual and erect image is

Ans- positive

Question-51. Which mirror do dentists use to see the larger image of patients' teeth?

Ans- concave mirror

Question-52. Which mirror is used as a shaving mirror?

Ans- concave mirror

Question-53. Which mirror has the largest field of vision?

Ans- convex mirror

Question-54. No matter how far you stand from a mirror, your image will always appear straight.

Ans- in plane and convex mirror

Question-55. What is the magnification of the image in a plane mirror?

Ans- +1

Question-56. The focal length of a mirror is f= +30 cm. Is it a concave mirror or a convex mirror?

Ans- Since the value of focus distance is positive. Hence it will be a convex mirror.

Question-57. By what other names are concave mirror and convex mirror known?

Ans-

concave mirror → converging mirror

convex mirror→ diverging mirror

Question-58. The image formed by a concave mirror of an object is found to be virtual, erect and larger than the object, then where should the position of the object be?

Ans- between the pole of the mirror and the principal focus

Question-59. What is the relationship between focal length and radius of curvature in a spherical mirror?

Ans- f = r/2

Question-60. If the magnification produced by a mirror is m=-2, which mirror will it be?

Ans- concave mirror

Question-61. If the magnification produced by a mirror is m = +1/2, which mirror will it be?

Ans- convex mirror

Question-62. Which large mirror is used to focus sunlight in solar furnaces?

Ans- concave mirror

Question-63. What is the value of angle of reflection for a ray of light incident normally on a plane mirror?

Ans- zero (0 degree)

Question-64. Which mirror forms the larger image of the object?

Ans- concave mirror

Question-65.If the radius of curvature (R) of a spherical mirror is 20 cm, what will be its focal length (f)?

Ans- 10 cm

Question-66. If the focal length (f) of a spherical mirror is 20 cm, what will be its radius of curvature (R)?

Ans- double

Question-67. In which mirror only imaginary images are formed?

Ans- in a convex mirror

Question-68. Rays of light travel—

Ans- in a straight line

Question-69. Searchlight has a reflective surface.

Ans- concave

Question-70. Which mirror is suitable for solar cooker?

Ans- concave mirror

Question-71. The diameter of the circular boundary line of the reflecting surface of a spherical mirror is called?

Ans- principal axis

Question-72. Which of the following is the focal length of a convex mirror whose radius of curvature is 32 cm.

(a) +8 cm (b) -8 cm (c) +16 cm (d) -16 cm

Ans- (c) +16 cm

Question-73. If the magnification of the image of an object is negative, what will be the nature of that image?

Ans- real and reverse

Question-74. According to the new Cartesian sign convention, the distance of the object placed in front of the mirror is taken as?

Ans- negative

Question-75. Which mirror has a positive focal length?

Ans- of convex mirror

Question-77. Where will the image be of the same size when the object is placed in front of a concave mirror?

Ans- at the center of curvature