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A myopic person's far point is 50 cm. The corrective lens has power:
A-2 D
B+2 D
C-0.5 D
D+0.5 D
Answer & Solution
Correct answer: A. -2 D
1. Form image of infinity at 50 cm in front of the lens.
2. u → ∞, v = -0.5 m, so f = -0.5 m and P = 1/f = -2.
3. Hence a concave lens of power -2 D.
_Source: NCERT Class 10 Science, Ch 10 "The Human Eye and the Colourful World", §10.2_
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