X Human Eye and the Colourful World (MCQ)Multiple choice questions

Multiple choice questions

1. When we enter a cinema hall, we cannot see properly for a short time. This is because-

a) Pupil does not open                                                 b) Pupil does not close

c) Adjustment of size of pupil takes some time            d) None of these above                                Ans: (c)

2. The property of persistence of vision is used in-

a) Short sightedness b) Long sightedness c) Cinematography d) Colour vision                               Ans: (c)

3. Variable focal length of eye is responsible for-

a) Accommodation of eye b) Persistence of vision

c) Colour blindness d) Least distance of distinct vision                                                                    Ans: (a)

4. A concave lens of suitable focal length is used for correcting a-

a) Myopic eye b) Hypermetropic eye c) Both a and b d) nor a nor b                                                Ans: (a)

5. Splitting of white light into seven colours on passing through the glass prism is called-

a) Reflection b) Refraction c) Scattering d) Dispersion                                                                     Ans: (d)

6. The broad wavelength range of visible spectrum is-

a) 4000-8000A                b) 2000-4000A               

c) 10000-20000A    d) None of the above            Ans: (a)

7. For which colour, refractive index of glass is maximum?

a) Red b) Violet c) Green d) Yellow                                                                                                    

Ans: (b)

8. Which colour suffers least deviation on passing through a prism?

a) Red b) Violet c) Indigo d) Blue                                                                                                      

Ans: (a)

9. Blue colour of sky is due to-

a) Scattering of light b) Reflection of light c) Refraction of light d) Diffraction of light                      

 Ans: (a)

10. Clouds appear red due to Rayleigh scattering. The statement is-  a) True b) False                  

Ans: (b)

11. Red colour of the sun at the time of sunrise and sunset is because-

a) Red colour is least scattered                                  b) Blue colour is least scattered

 c) Red colour is scattered the most                         d) All colours are equally scattered                   

Ans: (a)

12. A human eye can focus objects at different distances by adjusting the focal length of the eye lens. This is due to –  (a)Persistence of vision   (b)Near sightedness (c)Accommodation  (d)Far sightedness        Ans: (c)

13. Cinematography makes use of -         (a) Accommodation                 (b) Persistence of vision  

(c) Least distance of distinct vision (d) Bi-focal lens system                                                                   Ans: (b)

14. Human eye forms the image of an object at its –

(a)Cornea  Pupil  Iris  Retina                                                                                                          

Ans: (d)

15. The change of focal length of an eye lens to focus the image of objects at varying distances is done by the action of the -  (a)Pupil  (b)Retina  (c)Ciliary muscles  (d)Blind spot                                               Ans: (c)

16. The convex lens of focal length 20cm each are separated by a distance of 10cm for focal length of combination is :-  (a) 20cm  (b) 40cm (c) 30cm (d) 13.3cm                                                                       Ans: (d)

17. Two convex lenses of focal length 10cm and 20cm are kept in contact .The focal length of the combination is:          (a) 20/3 cm  (b) 40 cm            (c) 12cm      (d) 15 cm                                                                Ans: (a)

18. Two lenses of power –1.75D and +2.75D are placed in contact. The focal length of the combination is :-

(a)50cm         (b)100cm          (c)  75cm       (d)       125cm                                                                     Ans: (b)

19. Which eye piece satisfies the condition for spherical aberration:-

(a)Huygen’s eye piece         (b)Ramsden’s eye piece        (c)Both a and b  (d)None of the above     

 Ans: (a)

20. A myopic person cannot see clearly:-

(a)Distant objects   (b)Near objects  (c)Near and distant objects  (d)None of the above                     

Ans: (b)

21. A long-sighted person cannot see clearly:

(a)Near objects               (b) Distant objects        (c) Both distant and near objects      (d) None         

Ans: (a)

22. A person having Presbyopia should use:-

(a)Convex lens             (b) Concave lens   (c) Cylindrical lenses               (d) Bifocal lenses                 Ans: (d)

23. A person cannot see fundamental colours (red, blue, green). This defect is called:-

(a) Myopia          (b) Presbyopia            (c) Colour blindness         (d) Astigmatic                                  Ans: (c)

24. The defect of astigmatism can be rectified by using: -

(a)Convex lens          (b)  Cylindrical lens       (c) Concave lens         (d )  Bifocal lens                          Ans: (b)