Chapter 16, Problem 1DQ

To determine

The changes in the frequency, speed and wavelength of the sound when it is travels from air into water.

Answer to Problem 1DQ

The frequency of sound wave doesn’t changes when it is travels from air into water. The speed of the sound changes when it travels from air into water. The wavelength of the sound changes when it travels from air into water.

Explanation of Solution

Section 1:

To determine: The changes in the frequency of the sound when it travels from air into water.

Explanation: The frequency of sound is defined as the number of vibrations that an individual particle of the source makes per unit time. The frequency of a sound wave is only depends on the source of the wave irrespective of the flowing medium. Thus, the frequency of the sound will not change when it is travels from air into water.

Therefore, the frequency of sound wave doesn’t changes when it is travels from air into water.

Section 2:

To determine: The changes in the speed of the sound when it travels from air into water.

Explanation: The speed of sound depends on the properties of the medium through which it is travels and its speed changes from medium to medium. The sound wave travels faster in medium having higher density and decreases as the density of the medium decrease. Thus, the speed of the sound will change when it is travels from air into water.

Therefore, the speed of the sound changes when it travels from air into water.

Section 3:

To determine: The changes in the wavelength of the sound when it travels from air into water.

Explanation:

Formula to calculate the wavelength of sound wave is,

$\lambda =\frac{v}{f}$

• $\lambda$ is the wavelength.
• $v$ is the speed of the sound.
• $f$ is the frequency.

From the explanation in section 1 and section 2, the frequency of the sound doesn’t changes when the sound travels from air into water, but the frequency does. Since the wavelength of the sound wave is directly proportional to the speed of the sound, so when the speed changes the wavelength will also changes. Thus, the wavelength of the sound changes when it travels from air into water.

Therefore, the wavelength of the sound changes when it travels from air into water.

Conclusion:

The frequency of sound wave doesn’t changes when it is travels from air into water. The speed of the sound changes when it travels from air into water. The wavelength of the sound changes when it travels from air into water.