Question

A person suffering from an eye defect uses lenses of power −1 D. Name the defect of vision and list its two causes. State the nature (converging/diverging) of the correcting lens.

Answer 1

1. Defect of Vision and Corrective Lens: The person suffering from an eye defect and using lenses with a power of −1 D has myopia or nearsightedness.
2. Causes of Myopia:
   1. Elongation of the Eyeball: Myopia occurs when the eyeball is longer than normal, causing light to focus in front of rather than on the retina.
   2. Increased Curvature of the Cornea or Lens: Excessively curved the cornea or lens may cause light to focus in front of the retina.
3. Nature of Corrective Lens: The corrective lens for myopia is divergent. A diverging lens spreads light rays before entering the eye, allowing them to properly focus on the retina.