1. Light is a form of ------- that we can detect with our ---------
(a) Energy, ears
(b) Corpuscles, eyes
(c) energy, eyes
(d) Sensation, skin
2. The unit of power of a lens is
(a) Metre
(b) Dyne
(c) Dioptre
(d) None of these
3. The unit of refractive index is
(a) Metre
(b) Degree
(c) Diopre
(d) It has no units
4. A simple magnifying glass consists of a
(a) Concave lens
(b) Convex lens of large focal length
(c) Convex lens of small focal length
(d) Plane mirror only
5. The eye lens is a
(a) Transparent double-convex lens
(b) Transparent double-concave lens
(c) Transparent concavo-convex lens
(d) None of these
6. Long-sightedness is caused by the eyeball being too short, it can be corrected by the use of a
(a) Convergent lens
(b) Plane mirror
(c) Divergent lens
(d) None of these
7. Astigmatism occurs when the cornea does not have a truly spherical shape. This defect can be cured by the use of a
(a) Concave lens
(b) Cylindrical lens
(c) Convex lens
(d) Plano-convex lens
8. The power of a lens being + 4 dioptres suggests
(a) Convex lens
(b) Plano-convex lens
(c) Concave lens
(d) None of these
9. The amount of light entering in the eye is controlled by the
(a) Pupil
(b) Iris
(c) Cornea
(d) Eye lens
10. A green leaf placed in dark room is illuminated by red light. The leaf will appear to be
(a) Green
(b) Red
(c) Yellow
(d) Black
11. An object looks red when seen through a piece of red glass. What is the actual colour or the object?
(a) Red only
(b) White only
(c) Red or green
(d) Black
12. A pencil dipped into water at an angle appears broken due to ---- of light.
(a) Dispersion
(b) Reflection
(c) Refraction
(d) None of these
13. A swimming pool looks shallower than it really is, when seen by a person standing outside near it, because of the phenomenon of --------- of light.
(a) Refraction
(b) Reflection
(c) Dispersion
(d) None of these
14. In optical instruments, the lenses are used to form images by
(a) Reflection
(b) Refraction
(c) Dispersion
(d) Scattering
15. A lens which is thicker in the middle and thinner at the edges is called a ------- lens.
(a) Convex
(b) Concave
(c) Cylindrical
(d) None of these
16. A lens which is thinner at the middle and thicker at the edges is called a ------- lens.
(a) Convex
(b) Concave
(c) Cylindrical
(d) None of these
17. The power of a lens is a measure of its degree of
(a) Convergence only
(b) Divergence only
(c) Convergence or divergence
(d) None of these
18. Most of the refraction of light takes place in the
(a) Iris
(b) Cornea
(c) Pupil
(d) Retina
19. The central circular aperture of --------- is called -------------.
(a) Iris, pupil
(b) Pupil, iris
(c) Retina, iris
(d) None of these
20. When the light is very bright,
(a) The iris makes the pupil expand
(b) The iris makes the pupil contract
(c) The iris and the pupil remain as they are
(d) None of these
21. Our eye is a
(a) Convex lens
(b) Concave lens
(c) Plano-convex lens
(d) None of these
22. The eye lens is held in position by
(a) Rods and cones
(b) Iris and pupil
(c) Ciliary muscles
(d) None of these
23. The 'far point' of a normal human eye is
(a) 25 cm
(b) 25 m
(c) 100 m
(d) At infinity
24. Hypermetropia is due to the ------- of the eye.
(a) Low converging power
(b) Low diverging power
(c) High converging power
(d) High diverging power
25. Long-sightedness is to hypermetropia as short-sightedness is to
(a) Myopia
(b) Focussing
(c) Astigmatism
(d) Accommodation
26. The human eye forms the image of an object at its
(a) Cornea
(b) Iris
(c) Pupil
(d) Retina
27. The change in focal length of an eye-lens to focus the image of object at varying distances is done by the action of the
(a) Pupil
(b) Ciliary muscles
(c) Retina
(d) Blind spot
28. A magnifying glass comprises a simple
(a) Convex lens
(b) Convex mirror
(c) Concave lens
(d) Concave mirror
29. Which of the following optical instruments consists of two converging lenses?
(a) Compond microscope
(b) Simple microscope
(c) Electron microscope
(d) Galileon telescope
30. Sunlight is predominantly a mixture of -------- visible colours.
(a) 5
(b) 6
(c) 7
(d) None of these
31. Colour blindness is due to
(a) The absence of cone cells
(b) The presence of rod cells
(c) The absence of rod cells
(d) None of these
32. The rod cells correspond to
(a) The colour of light
(b) The source of light
(c) The intensity of light
(d) None of these
33. Which of the following colours of light undergoes the least deviation while passing through a glass prism?
(a) Red
(b) Blue
(c) Yellow
(d) Green
34. Which of the following sources of light is different from others?
(a) Sunlight
(b) White light
(c) Light from a bulb
(d) Sodium light
35. The combination of red light and blue light is
(a) Yellow light
(b) Green light
(b) Light of magenta colour
(c) Light of white colour
36. Which colour of light is produced on mixing green with magenta?
(a) White
(b) Red
(c) Yellow
(d) None of these
37. The colour complementary to yellow is
(a) Blue
(b) White
(c) Red
(d) Green
38. A red grass in white light appears
(a) Red
(b) Green
(c) Yellow
(d) None of these
39. Which of the following colours cannot be produced by mixing other colours?
(a) Red, blue, green
(b) Red, Yellow, green
(b) Blue, green, cyan
(c) Magenta, yellow, cyan
40. The cyan colour is commonly known as
(a) Peacock colour
(b) Blood red
(c) Sky blue
(d) None of these
41. How should people wearing spectacles work with a microscope?
(a) They should keep on wearing their spectacles.
(b) They should never use the microscope.
(c) They should take off their spectacles.
(d) They may either either put on their spectacles or they may take off their spectacles.
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