Question:medium
A train moving at 20 m/s approaches a stationary observer. The frequency of the whistle emitted by the train is 640 Hz. If the velocity of sound is 340 m/s, the apparent frequency heard by the observer is:
A train moving at 20 m/s approaches a stationary observer. The frequency of the whistle emitted by the train is 640 Hz. If the velocity of sound is 340 m/s, the apparent frequency heard by the observer is:
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Key Exam Tip:
For Doppler effect, when source approaches observer, use ($v - v_s$) in the denominator to increase frequency.
For Doppler effect, when source approaches observer, use ($v - v_s$) in the denominator to increase frequency.
Updated On: May 16, 2026
- 680 Hz
- 600 Hz
- 720 Hz
- 640 Hz
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The Correct Option is C
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