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A sound of frequency 850 Hz travels in air at 340 m/s.

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Try it on paper first. A hint, the key idea and the worked solution are here when you need them.

A sound of frequency $850\ \text{Hz}$ travels in air at $340\ \text{m/s}$ . It then goes into water, where its speed is $1530\ \text{m/s}$ . Find the wavelength in air and in water. Which quantity does not change?

Need a reminder? The key ideaShow

Frequency $f$ (waves each second, in $\text{Hz}$ ), time period $T = \dfrac{1}{f}$ , wavelength $\lambda$ (compression to compression), and $v = f\lambda$ . The medium sets $v$ ; the source sets $f$ .

The worked solution

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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.

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