Question
The focal length of a concave lens is 0·5 m. The power of the lens is
NDA
General Ability
General Science
2025
NDA 2025 (Phase 2)
NDA General Ability Question (2025) — Solution
Options
- A. +0·5 D
- B. −0·5 D
- C. +2·0 D
- D. −2·0 D
Answer
D. −2·0 D
Step-by-step solution
The focal length of a concave lens is taken as negative. f = -0 5 m The power of a lens is given by P = 1 f P = 1 -0 5 = -2 0 D Answer: −2·0 D
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