Longitudinal Wave Physics Example 2

Follow the full solution, then compare it with the other examples linked below.

Example 2

medium

Sound travels at

340 \text{ m/s}

in air and

5100 \text{ m/s}

in steel. A

1000 \text{ Hz}

sound wave enters a steel rail. What is the wavelength in each medium?

Solution

1
In air: $\lambda_{\text{air}} = \frac{v_{\text{air}}}{f} = \frac{340}{1000} = 0.34 \text{ m}$ .
2
In steel: $\lambda_{\text{steel}} = \frac{v_{\text{steel}}}{f} = \frac{5100}{1000} = 5.1 \text{ m}$ .
3
The frequency stays the same in both media, but the wavelength changes with the speed.

Answer

\lambda_{\text{air}} = 0.34 \text{ m}, \quad \lambda_{\text{steel}} = 5.1 \text{ m}

Sound is a longitudinal wave that travels faster in denser, stiffer media. When a wave enters a new medium, its frequency stays constant but its wavelength and speed change.

About Longitudinal Wave

A wave in which the particles of the medium oscillate parallel to the direction of wave propagation, creating alternating regions of compression (high pressure) and.

Learn more about Longitudinal Wave →

More Longitudinal Wave Examples

Example 1 easy

A longitudinal wave in a spring has compressions [formula] apart. The wave frequency is [formula]. W

Example 3 medium

An ultrasound device emits sound at [formula] in human tissue ([formula]). What is the wavelength? W

Example 4 hard

An earthquake produces both P-waves ([formula], longitudinal) and S-waves ([formula], transverse). A

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Related Concepts

Waves Sound Pressure Wave