(a) Write about the two defects of vision (i) Myopia and (ii) Hypermetropia, How they can be removed?
(b) What do you mean by the total internal reflection? Give the two conditions for TIR of light to take place.
Answers
Myopia/Nearsightdness
1) In these defect eye can see near object clearly but appear distant object Indistinct.
2)In Mayopia the image of distant object is form in front of retina.
3)Two reason for these defect:
a)The curvature of cornea and eyelens increases.
b)The eyeball is elongated so the distance between the lens & retina increses.
4)These defect can be removed by using spectacles with concave lens.
Hypermetropia/Farsightdness
1) In these defect eye can see distant object clearly but cannot see near by object clearly.
2)In the farsightdness the image of near by object is form behind the retina.
3)Two reason for this defect.
a)The curvature of cornea and eyelens is decreses.
b)The eyeball is flat, so the distance between the lens and retina decreases.
4)The defect can be removed by using spectacles with convex lens.