Question

Which type of lenses are used in spectacles for the correction of Myopia of the eyes?
A. Convex lenses
B. Concave lenses
C. Both convex and concave lens
D. None of the above

Answer 1

Hint: Lenses are widely used for the correction for problems of eyes in which a person is not able to see correctly. There can be many kinds of eye problems and not necessarily all of them require a lens to correct it. Spectacles broadly uses two types of lens either concave or convex. Some eye conditions require a combination of both of them.

Complete answer:
The person is suffering from near-sightedness. It is a condition in which close objects appear clearly, but far ones do not appear sharp. This type of eye problem is called myopia.The objects that are at a distance or nearby can be focused by the human eye due to its abilities.To watch objects that are nearby and focus on them the lens of the eye has a short focal length.

If the curvature of the lens is large it will be able to focus on closer objects whereas if the curvature is small it will be able to focus on objects further far away. Most of the time, the effects of the defect start showing up at the extreme ends of the visual spectrum. Myopia can be corrected by using a diverging lens that is concave. Since the image is being formed before the retina so concave lens diverges the rays passing through it and then the image is formed on the retina.

So, the correct option is B.

Note:The use of lenses to correct the problems being faced is widely used. There can be two major eye problems: one is in which a person is not able to see nearby objects clearly, this is hypermetropia and this can be corrected using convex lenses. The other is myopia which we have discussed above. The cause of myopia image is formed at some distance before the retina but not at the retina.