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What kind of spectacle lens corrects farsightedness, and how does it help?
AA converging lens, which raises the eye's effective power
BA diverging lens, which lowers the eye's effective power
CA flat lens, which leaves the eye's power completely unchanged
DA curved mirror, which reflects the image onto the retina
Answer & Solution
Correct answer: A. A converging lens, which raises the eye's effective power
1. A farsighted eye underconverges light because its focal length is effectively too long.
2. Correcting this uses a converging spectacle lens, which increases the power of an eye that has too long a focal length.
3. A diverging lens would only reduce the eye's power further, worsening the underconvergence instead of fixing it.
_Source: OpenStax Physics (CC BY 4.0), Ch 16 "Mirrors and Lenses", section 16.3 Lenses_
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