The human eye and the colourful world Worksheet-1

The human eye and the colourful world Worksheet-1

1. The human eye can focus objects at different distances by adjusting the focal length of the eye lens. This is due to

A. presbyopia                                B. near sightedness

C. accommodation                       D. far-sightedness

2. The human eye forms the image of an object at its

A. cornea           B. pupil              C. iris                  D. retina

3. The least distance of distinct vision for a young adult with normal vision is about 

A. 25 m              B. 25 cm            C. 2.5 cm           D. 2.5 m

4. The change in focal length of an eye lens is caused by the action of the

A. pupil              B. retina             C. iris                  D. ciliary muscles

5. The size of the pupil of the eye is adjusted by

A. cornea           B. retina             C. iris                  D. yellow point

6. 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 the size of pupil takes some time

D. none of these

7. When we go out in bright sunlight, the pupil of the eye

A. contracts

B. expands

C. sometimes contracts and sometimes expands

D. neither contracts nor expands

8. Which cells respond to colour of light?

A. rod shaped cells                       B. cone shaped cells

C. both types of cells                    D. neither of the two

9. Eye lens is a

A. double convex lens                  B. double concave lens

C. piano convex lens                    D. piano concave lens

10. The property of persistence of vision is used in

A. short sightedness                    B. long sightedness

C. cinematography                      D. colour vision

Answer Key:

1. C

Explanation: The property of the eye to adjust the focal length of eye lens is called accommodation.

2. D

Explanation: The human eye forms the image of an object at its retina.

3. C

Explanation: The least distance of distinct vision for a young adult with normal vision is 25 cm.

4. D

Explanation: The action of ciliary muscles holding the eye lens changes the focal length of eye lens enabling the eye to focus the image of objects at varying distances.

5. C
6. C

Explanation: Change in the size of the pupil by the iris takes some time.

7. A

Explanation: In bright sunlight, pupil of the eye contracts so as to allow only a little light to enter the eye.

8. B
9. A
10. C

Explanation: The property of persistence of vision is used in projection of still pictures taken by a movie camera.