Q3 of 102 Page 130

The figure below compares a part of our eye with a part of a photographic camera


(a) Name the corresponding parts of the eye and the camera shown here that are comparable in function.


(b) Explain the mode of working and the function of the parts of the eye mentioned above.

(a) Cornea is comparable to the lens cover of the camera. The iris and pupil act like the aperture of a camera.


(b) The cornea is the eye's main focusing element. It takes widely diverging rays of light and bends them through the pupil; the rays are further converged by the lens.


More from this chapter

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1

With reference to the functioning of the eye, answer the questions that follow:

(a) What is meant by the power of accommodation of the eye?


(b) What is the shape of the lens during (1) near vision (2) distant vision ?


(c) Name the two structures in the eye responsible for bringing about the change in the shape of the lens.


(d) Name the cells of the retina and their respective pigments which get activated

 2

With reference to the human ear, answer the questions that follow:

(a) Give the technical term for the structure found in the inner ear.


(b) Name the three small bones present in the middle ear.


What is the biological term for them collectively?


(c) Name the part of the ear associated with


(d) Name the nerve, which transmits messages from the ear to the brain.

 4

Given below is a diagram depicting a defect of the human eye. Study the same and answer the questions that follow:


(a) Name the defect shown in the diagram.


(b) Give two possible reasons for this defect.


(c) Name the parts labelled 1 to 4.


(d) Name the type of lens used to correct this eye defect


(e) Draw a labelled diagram to show how the above-mentioned defect is rectified using the lens named above.

 5

The figure below is the sectional view of a part of the skull showing a sense organ:


(i) Name the sense organ.


(ii) What are the parts labeled “m”, “I” and “s”? What do these parts constitute collectively?


(iii) What do you call the part shown in the form of a spiral? What is its function?


(iv) Name the part labeled “to”? What is its function?