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A myopic person has a far point of 1 m. The focal length of the corrective concave lens is:
Answer & Solution
Correct answer: C.
1. The corrective lens must form the image of infinity at the far point (1 m in front).
2. For lens formula with u = ∞, v = -100 cm, we get f = -100 cm.
3. Hence a concave lens of focal length -100 cm (power -1 D) is needed.
_Source: NCERT Class 10 Science, Ch 10 "The Human Eye and the Colourful World", §10.2_
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