Question
The engine of a train moving with speed 10 ~ms ^ -1 towards a platform sounds a whistle at frequency 400 ~Hz . The frequency heard by a passenger inside the train is (neglect air speed. Speed of sound in air 330 ~ms ^ -1 )
BITSAT
Physics
Waves and Sound
2023
BITSAT 2023 (Memory Based Paper 2)
BITSAT Physics Question (2023) — Solution
Options
- A. 200 ~Hz
- B. 400 ~Hz
- C. 412 ~Hz
- D. 388 ~Hz
Answer
B. 400 ~Hz
Step-by-step solution
The relative velocity of a passenger with respect to source of sound (engine of train) is 0 . So there will be no Doppler's effect. So frequency heard is 400 ~Hz .
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