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Topic Wavelength
Asked 5 times across 4 UPSC exams over 38 years (1985–2023), peaking in 1985.
Key insights
- Most tested in CSE — 2 of 5 PYQs
- Most asked in 1985
- Recurs across 5 years (1985–2023)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
CSE 1985 → CDS 2014 → NDA 2020 → CISF 2023
How the concept evolved
Long-running — most appearances (3 of 5) predate 2016, and it still returns.
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.
CISF2023
Which one of the following represents the correct order for the wavelengths of different waves?
- A Used for FM radio > Used for AM radio > Microwaves > Infrared > Visible light
- B Used for AM radio > Used for FM radio > Microwaves > Infrared > Visible light ✓
- C Used for AM radio > Used for FM radio > Infrared > Visible light
- D Used for AM radio > Used for FM radio > Infrared > Visible light > Microwaves
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
NDA2020
Which one of the following types of radiations has the smallest wavelength ?
- A Microwaves ✓
- B Infra-red
- C Visible light
- D X-rays
✓ Correct answer: (A)
Science & Technology › Physics & Chemistry
CDS2014
In the phenomenon of dispersion of light, the light wave of shortest wavelength is
- A accelerated and refracted the most
- B slowed down and refracted the most ✓
- C accelerated and refracted the least
- D slowed down and refracted the least
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
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