9. Ray optics abd optical instruments — Physics STD 12 Science — Question
CBSE BoardEnglish MediumSTD 12 SciencePhysics9. Ray optics abd optical instruments1 Mark
MCQ
A myopia patient uses
A
Convex lens
✓
Concave lens
C
Cylindrical lens
D
Bifocal lens
✓
Answer
Correct option: B.
Concave lens
b Near sightedness, or myopia, is the most common refractive error of the eye. Myopia occurs when the eyeball is too long, relative to the focusing power of the cornea and lens of the eye. This causes light rays to focus at a point in front of the retina, rather than directly on its surface. So, to treat myopia the glasses will be preceded by a minus sign $().$ Hence, to treat myopia concave lens should be used.
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