How does the wavelength of a sound wave change as the source of the sound approaches or moves away from the listener?
When the source of a sound wave approaches or moves away from a listener, it affects the wavelength of the sound wave. The wavelength is the distance between two consecutive points on a wave, such as two crests or two troughs.
If the source of the sound wave is approaching the listener, the wavelength decreases. This is due to a phenomenon called "Doppler effect." As the source moves closer, the sound waves become compressed, leading to a shorter distance between successive crests or troughs. This results in an increase in the frequency of the sound wave, which is perceived as a higher pitch by the listener.
Conversely, when the source of the sound wave moves away from the listener, the wavelength increases. The sound waves become stretched out, causing a longer distance between consecutive crests or troughs. This leads to a decrease in the frequency of the sound wave, resulting in a lower pitch perception by the listener.
In summary, as the source of a sound wave approaches, the wavelength decreases, and as it moves away, the wavelength increases. This change in wavelength affects the perceived pitch of the sound observed by the listener.
The wavelength of a sound wave changes as the source of the sound approaches or moves away from the listener due to the phenomenon known as the Doppler effect. The Doppler effect describes the perceived change in frequency and wavelength of a wave as the source and observer move relative to each other.
When a source of sound approaches a listener, the waves get compressed, resulting in a higher frequency and shorter wavelength. This is known as a "blue shift" because, in visible light, blue light has a higher frequency compared to red light. Similarly, when a source of sound moves away from a listener, the waves get stretched, resulting in a lower frequency and longer wavelength. This is known as a "red shift" for the same reason.
To calculate the change in wavelength, you need to know the relative velocity of the source and the observer. The formula for calculating the shifted wavelength (λ') is:
λ' = λ * (v + v_obs) / (v + v_source),
where λ is the initial (or rest) wavelength of the sound wave, v is the speed of sound in the medium it is traveling through, v_obs is the velocity of the observer relative to the medium, and v_source is the velocity of the source relative to the medium.
By using this formula, you can determine how the wavelength of a sound wave changes as the source of the sound approaches or moves away from the listener.