Saturday, December 8, 2012

CBSE Class 10 - Physics - CH11: The Human Eye and the Colourful World (Worksheet)

The Human Eye and the Colourful World
Human Eye

Fill in the blanks

1. The transparent spherical membrane covering the front of the eye is called ____________.

2. _______ is the surface which acts as screen and image is formed on it.

3. The coloured diaphragm between cornea and lens is known as __________.

4. A small hole in iris which controls the intensity of light entering the eye is called __________.

5. ____________ muscles hold the position of the lens and adjust its thickness.

6. The point on retina at which optic nerve leaves the eye is called ___________. At this point if any image formed is not sent to the brain.

7. A point on retina which has highest concentration of sensitive cells and forms a clear image when we see any object minutely, is called __________.

8. The ability of eye lens to focus near and far objects clearly on retina by adjusting is focal length is called the _______________ of the eye.

9. For a young human adult with normal vision, the near point is about ___________ and it is denoted by ______.

10. For a young human adult with normal vision, the far point is at __________.

11.  To see objects with both eyes together is called _________ vision.

12. A transparent alkaline liquid between cornea and lens is called ___________. It helps in ________ of light rays in cornea.

13. A jelly fluid filling the space between lens and retina is called _________. It with stands atmospheric pressure and prevents eye ball from  collapsing.

14. Human is made up of ___________ jelly fluid material and it is a _________  __________ lens.

15. In __________ distant objects are not clearly visible. It is corrected by using ________ lens.

16. In ___________ objects nearby are not distinctly visible. It is corrected by using _______ lens.

17. ________ occurs due to weakening of ciliary muscles in old age. It can be corrected by using __________ lenses.

18. Power of a spherical lens is the reciprocal value of its _______________.

1: cornea
2: retina
3: Iris
4: pupil
5: Cilliary
6: Blind Spot
7: Macula or yellow spot.
8: accommodation
9: 25 cm, D
10: infinity (∞)
11: binocular
12: aqueous humour, refraction
13: vitreous humour
14: crystalline, double, convex
15: myopia, concave
16: hypermetropia, convex
17: Presbyopia, bi-focal
18: focal length


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