Advertisements
Advertisements
प्रश्न
Distinguish between the following pair of words:
Myopia and hypermetropia
Advertisements
उत्तर
| Myopia | hypermetropia |
| (i) The image of distant object is produced in the front and not on the retina . | (i) The image is produced beyond the retina as the light rays are unable to converge on the retina. |
| (ii) It results from abnormally long eyeball . | (ii) It results from abnormally short eyeball. |
| (iii) The defect can be produced by high convexity of the lens . | (iii) The defect can be produced by low convexity of the lens . |
| (iv) It can be corrected by the use of spectacles having concave lens . | (iv) It can be corrected by the use of spectacles having convex lens . |
APPEARS IN
संबंधित प्रश्न
Write the importance of ciliary muscles in the human eye. Name the defect of vision that arises due to gradual weakening of the ciliary muscles. What types of lenses are required by the person suffering from this defect to see the objects clearly?
Akshay, sitting in the last row in his class, could not see clearly the words write on the blackboard. When the teacher noticed it, he announced if any student sitting in the front row could volunteer to exchange his seat with Akshay. Salman immediately agreed to exchange his seat with Akshay. He could now see the words written on the blackboard clearly. The teacher thought it fit to send the message to Akshay’s parents advising them to get his eyesight checked.
In the context of the above event, answer the following questions:-
(a) Which defect of vision is Akshay suffering from? Which type of lens is used to correct this defect?
(b) State the values displayed by the teacher and Salman.
(c) In your opinion, in what way can Akshay express his gratitude towards the teacher and Salman?
A student suffering from myopia is not able to see distinctly the objects placed beyond 5 m. List two possible reasons due to which this defect of vision may have arisen. With the help of ray diagrams, explain
(i) why the student is unable to see distinctly the objects placed beyond 5 m from his eyes.
(ii) the type of the corrective lens used to restore proper vision and how this defect is corrected by the use of this lens.
(b) If, in this case, the numerical value of the focal length of the corrective lens is 5 m, find the power of the lens as per the new Cartesian sign convention
What is the scientific name of
long-sightedness?
What is the other name of old age hypermetropia?
Your friend can read a book perfectly well but cannot read the writing on blackboard unless she sits on the front row in class.
Is she short-sighted or long-sighted?
A student sitting in the last row of the class-room is not able to read clearly the writing on the blackboard.
How can this defect by corrected?
A person can read a book clearly only if he holds it at an arm's length from him. Name the defect of vision:
if the person is an old man
Give Reason:
Deficiency of vitamin A causes night blindness.
Observe the given below the figure, correct it and explain and write about the concept depicted in this figure.
Given below is a diagram showing a defect of vision. Name the defect of vision and draw an accurately labelled diagram to correct this defect.
