When sound wave is refracted from air to water, which of the following will remain unchanged?

Options

A. wave number
B. wavelength
C. wave velocity
D. frequency

Answer

To solve the question of which parameter remains unchanged when a sound wave is refracted from air to water, we can follow these steps:

### Step 1: Understand the parameters involved in sound waves.
- The parameters we need to consider are:
- Wave number
- Wavelength
- Wave velocity
- Frequency

### Step 2: Recall the behavior of sound waves during refraction.
- When sound waves travel from one medium to another (in this case, from air to water), certain properties change while others remain constant.

### Step 3: Identify what changes and what remains constant.
- **Frequency**: The frequency of a sound wave remains constant when it moves from one medium to another. This is because frequency is determined by the source of the sound and does not depend on the medium.
- **Wave velocity**: The speed of sound changes when it moves from air to water because sound travels faster in water than in air.
- **Wavelength**: The wavelength of the sound wave also changes when it moves from one medium to another, as it is related to both the speed of sound and frequency.
- **Wave number**: The wave number, which is related to the wavelength, will also change.

### Step 4: Conclusion
- Based on the above analysis, the only parameter that remains unchanged when a sound wave is refracted from air to water is the **frequency**.

### Final Answer
- The frequency of the sound wave will remain unchanged.

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