MediumPhysicsHigh School (9–10)GeneralWaves & Sound › Sound Waves and HearingNumericalConceptualBoard Exam
A dog whistle gives a sound of frequency 28 000 Hz…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A dog whistle gives a sound of frequency . A dog obeys it, but a person hears nothing.
- Why?
- What is the wavelength of this sound in air? (Speed of sound )
Need a reminder? The key ideaShow
Loudness depends on the amplitude, pitch on the frequency, and quality on the mixture of frequencies. People hear about to : below is infrasound, above is ultrasound.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. (a) is above : ultrasound for us, but within a dog's range.
Step 2. (b) , about .
Answer: it is ultrasound for people; .
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