A siren emitting 500 Hz moves at 68 m/s directly towards a stationary listener. Taking the speed of sound as 340 m/s, what frequency does the listener hear?
Answer and explanation
Correct answer: B. 625 Hz
- Step 1: For a source approaching a stationary observer, .
- Step 2: Hz.
Answer
625 Hz.
Why not the others: 416.7 Hz: it uses the formula for a receding source. 568 Hz: the speed of the source is added to the frequency. 400 Hz: the ratio is inverted.
Practise more Waves and Sound.
Free questions with an explanation for every one, and full timed EJU Japan mock tests.
More Waves and Sound questions
- A siren emitting 600 Hz moves at 68 m/s directly towards a stationary listener. Taking the speed of sound as 340 m/s, what frequency does th…
- A siren emitting 1000 Hz moves at 68 m/s directly towards a stationary listener. Taking the speed of sound as 340 m/s, what frequency does t…
- A siren emitting 1000 Hz moves at 170 m/s directly towards a stationary listener. Taking the speed of sound as 340 m/s, what frequency does…
- A open-ended (both ends open) tube of length 0.85 m has air at which the speed of sound is 340 m/s. What is the fundamental frequency?
- A closed-end (one end closed) tube of length 0.17 m has air at which the speed of sound is 340 m/s. What is the fundamental frequency?
- A closed-end (one end closed) tube of length 0.34 m has air at which the speed of sound is 340 m/s. What is the fundamental frequency?