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Topic Lens power
Asked 8 times across 3 UPSC exams over 4 years (2020–2024), peaking in 2022.
Key insights
- Most tested in NDA — 5 of 8 PYQs
- Most asked in 2022
- Recurs across 5 years (2020–2024)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
NDA 2020 → CDS 2020 → CAPF 2022
How the concept evolved
Rising — more than half its appearances (8 of 8) are since 2016.
Related concepts
Ideas UPSC tests alongside this one — keep exploring.
Sample questions
You've seen the pattern — here are a few of the actual PYQs.
NDA2024
Which one among the following is the correct focal length of a combination of lenses of power 2.5 D and -2.0 D ?
- A +0.5 m
- B -0.5 m
- C +2.0 m ✓
- D -2.0 m
✓ Correct answer: (C)
Science & Technology › Physics & Chemistry
CDS2023
The power of a lens of focal length 10 cm is
- A 0.1 dioptre
- B 1 dioptre
- C 10 dioptre ✓
- D 100 dioptre
✓ Correct answer: (C)
Science & Technology › Physics & Chemistry
NDA2023
Ramesh cannot see distinctly objects kept beyond 2 m. This defect can be corrected by using a lens of power
- A + 0.5 D
- B − 0.5 D ✓
- C + 0.2 D
- D − 0.2 D
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
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