Topicwise Questions - Lenses/Mirrors

1. Suppose you are standing 1 m in front of a plane mirror. What should be the minimum vertical size of the mirror so that you can see your full image in it?

  1. 0.50 m
  2. 2 m
  3. half of your height.
  4. twice your height.

2. A spherical air bubble is embedded in a piece of glass. For a ray of light passing through the bubble, it behaves like a :

  1. converging lens
  2. diverging lens
  3. plano-converging lens
  4. plano-diverging lens

3. Which one among the following is used to make periscope?

  1. Concave lens
  2. Concave mirror
  3. Plane mirror
  4. None of the above

4. What is the power of the lens, if the far point of a short-sighted eye is 200 cm?

  1. -0.5 D
  2. 2 D
  3. 1 D
  4. -1.5 D

5. The image formed by a convex mirror of a real object is larger than the object

  1. when u < 2f
  2. when u > 2f
  3. for all values of u
  4. for no value of u
(u – object distance, f – focal length )

6. The mirror used for the head light of a car is

  1. spherical concave
  2. plane
  3. cylindrical
  4. parabolic concave

7. The ratio of the focal length of the objective to the focal length of the eyepiece is greater than one for

  1. a microscope
  2. a telescope
  3. both microscope and telescope
  4. neither microscope nor telescope

8. The radius of curvature of a plane mirror

  1. is zero
  2. is infinity
  3. can be anywhere between zero and infinity
  4. None of the above

9. The human eye is like a camera and hence it contains a system of lens. The eye lens forms

  1. a straight or upright, real image of the object on the retina
  2. an inverted, virtual image of the object on the retina
  3. an inverted, real image of the object on the retina
  4. a straight or upright, real image of the object on the iris

10. An object is placed at the focus of a concave mirror. The image will be

  1. real, inverted, same size at the focus
  2. real, upright, same size at the focus
  3. virtual, inverted, highly enlarged at infinity
  4. real, inverted, highly enlarged at infinity

11. What kind of image is created by a concave lens?

  1. upright and smaller
  2. inverted and smaller
  3. inverted and larger
  4. upright and smaller

12. An optician prescribes a power = - 0.5 dioptre. The corresponding lens must be a

  1. convex lens of focal length 2 m
  2. convex lens of focal length 50 cm
  3. concave lens of focal length 2 m
  4. concave lens of focal length 50 cm

13. How far must a girl stand in front of a concave spherical mirror of radius 120 cm to see an erect image of her face four times its natural size?

  1. 40 cm from the mirror
  2. 45 cm from the mirror
  3. 50 cm from the mirror
  4. 55 cm from the mirror

14. How far must an object be from a concave mirror if the image formed is to be inverted?

  1. less than its focal length
  2. exactly at its focal length
  3. more than its focal length
  4. None of the above

15. What kind of lens is used by short-sighted persons?

  1. convex
  2. concave
  3. cylindrical
  4. compound

16. An object is kept 5 cm in front of a concave mirror of focal length of 15 cm. What will be the nature of the image?

  1. virtual, not magnified
  2. virtual, magnified
  3. real, magnified
  4. real not magnified

17. The head mirror used by E.N.T doctors is -

  1. Concave
  2. Convex
  3. Plane
  4. Plano-convex

18. What type of mirror is used in a view finding mirror of a vehicle?

  1. Convex mirror
  2. Concave mirror
  3. Plane mirror
  4. Paraboloidal mirror

19. A number of images of a candle flame can be seen in a thick mirror. The brightest image is -

  1. last
  2. fourth
  3. third
  4. second

20. What would be the number of images formed of an object in two mirrors placed at right angles to each other?

  1. two
  2. three
  3. four
  4. six

21. An object is placed at a distance of 12 cm from a convex lens on its principal axis and a virtual image of certain size is formed. If the object is moved further 8 cm away from the lens, a real image of the same size as that of the virtual image is formed . Which one of the following is the focal length of the lens?

  1. 15 cm
  2. 16 cm
  3. 18 cm
  4. 20 cm

22. Which of the following is incorrect?

  1. A concave mirror can give a magnified virtual image.
  2. A concave mirror can give a magnified real image.
  3. The virtual image given by a concave mirror is inverted.
  4. The real image given by a concave mirror is inverted.

23. Different objects at different distances are seen by the eye. The parameter that remains constant is

  1. the focal length of the eye lens
  2. the object distance from the eye lens
  3. the radii of culvature of the eye lens
  4. the image distance from the eye lens

24. What kind of image is formed by a concave lens irrespective of the position of the object?

  1. virtual, upright and diminised
  2. real, upright and diminished
  3. virtual, upright and magnified
  4. real, inverted and magnified