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A myopic person uses a lens of focal length -1.5 m. The power of this lens is:
A-0.67 D
B+0.67 D
C+1.5 D
D-1.5 D
Answer & Solution
Correct answer: A. -0.67 D
1. Power of a lens P = 1 / f (with f in metres).
2. Given f = -1.5 m.
3. Substitute: P = 1 / (-1.5) = -0.6666... D.
4. Rounded to two decimals, P approx -0.67 D.
5. The minus sign confirms a diverging (concave) lens, as expected for myopia.
_Source: NCERT Class 10 Science Ch 11 'Human Eye and the Colourful World'_
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