Q17 of 56 Page 1

What eye defect is myopia? Describe with a neat diagram how this defect of vision can be corrected by using a suitable lens.

Myopia is an eye-defect in which a person is unable to see the distant object but can see clearly the nearby objects.


The various causes of myopia are:


1. It is caused due to elongation of eye ball


2. It is caused due to decrease in the focal length of eye lens.


Myopia can be corrected by usage of a concave lens of suitable power.


The Ray diagram which shows the Myopic correction is:



More from this chapter

All 56 →
15

An object its placed between infinity and the pole of a convex mirror. Draw a ray diagram and also state the position, the relative size and nature of the image formed.

 16

What is the principal of reversibility of light? Show that the incident ray of light is parallel to the emergent ray of light when light falls obliquely on a side of a rectangular glass slab.

 18

What does HIV stand for? Is AIDS an infectious disease? List any four modes of spreading AIDS.

 19

A team of Indian researches went to Antarctica to study the ozone layer. They confirmed the presence of largest ozone hole over Antarctica and was just short of 27 million sq. km. After few days of their return, one of the scientist developed rushes, burning sensation and other skin problems which the doctor have confirmed as skin cancer.

(a) What may be the cause of cancer just after return from Antarctica?


(b) What do we learn from this incident?


(c) Raghav, a student of your school organizes a poster-making competition on the topic ‘save ozone’. What moral value is shown by Raghav? What other initiatives will you suggest in this regard?