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Topic Electromagnetic Spectrum
Asked 6 times across 3 UPSC exams over 8 years (2018–2026), peaking in 2023.
Key insights
- Most tested in NDA — 3 of 6 PYQs
- Most asked in 2023
- Recurs across 5 years (2018–2026)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
CDS 2018 → NDA 2022 → CISF 2023
How the concept evolved
Rising — more than half its appearances (6 of 6) 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.
CISF2026
With regard to night vision cameras, which one among the following is correct?
- A They detect infrared light.
- B They detect ultraviolet light.
- C They detect radio waves.
- D They detect microwaves.
Answer key not yet available (pending official release)
Science & Technology › Physics & Chemistry
NDA2024
Consider the two statements given below
Statement 1Infrared waves are also called heat waves
Statement 2Water molecules readily absorb infrared waves
Select the correct answer using the code given below:
- A Both the statements are individually true and Statement-2 is the correct explanation of Statement-1. ✓
- B Both the statements are individually true, but Statement-2 is not the correct explanation of Statement-1.
- C Statement-1 is true, but Statement-2 is false.
- D Statement-2 is true, but Statement-1 is false.
✓ Correct answer: (A)
Science & Technology › Physics & Chemistry
NDA2023
Which one of the following statements about X-rays is not true?
- A They have wavelengths of about 1 Å.
- B These can be generated by bombarding a metal target by high energy electrons.
- C Due to their wavelengths being shorter, these can be used for radar systems. ✓
- D These are also used for the treatment of certain forms of cancer.
✓ Correct answer: (C)
Science & Technology › Physics & Chemistry
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