Topic Frequency
Asked 5 times across 3 UPSC exams over 30 years (1994–2024), peaking in 2021.
Key insights
- Most tested in NDA — 3 of 5 PYQs
- Most asked in 2021
- Recurs across 4 years (1994–2024)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
CSE 1994 → NDA 2021 → CISF 2023
How the concept evolved
Rising — more than half its appearances (4 of 5) 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
The AC mains domestic supply current in India changes direction in every
- A 50 s
- B 1/50 s
- C 100 s
- D 1/100 s ✓
✓ Correct answer: (D)
Science & Technology › Physics & Chemistry
CISF2023
Which one among the following statements regarding sound is correct?
- A High pitch sound has high frequency ✓
- B High pitch sound has high amplitude
- C High pitch sound has high speed
- D High pitch sound has low frequency and high amplitude
✓ Correct answer: (A)
Science & Technology › Physics & Chemistry
NDA2021
Which one of the following cannot be the unit of frequency of a sound wave ?
- A dB ✓
- B s–1
- C Hz
- D min–1
✓ Correct answer: (A)
Science & Technology › Physics & Chemistry
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