A sound wave and a light wave are reflected and refracted (or transmitted) from water surface. Show the changes in different physical quantities associated with a wave.

Explanation

To analyze the changes in different physical quantities associated with a sound wave and a light wave as they are reflected and refracted at the water surface, we can break down the problem into several steps.

### Step-by-Step Solution

1. **Identify the Mediums**:
- For sound waves: Air is the denser medium, and water is the rarer medium.
- For light waves: Air is the rarer medium, and water is the denser medium.

2. **Draw the Incident, Reflected, and Refracted Waves**:
- Draw a normal line to the water surface.
- Indicate the incident wave approaching the surface, the reflected wave bouncing back, and the refracted wave entering the water.

3. **Apply Snell's Law for Refraction**:
- For sound waves (from denser to rarer medium):
- The angle of incidence (α) is greater than the angle of refraction (γ), meaning the wave bends away from the normal.
- For light waves (from rarer to denser medium):
- The angle of incidence (α) is less than the angle of refraction (γ), meaning the wave bends towards the normal.

4. **Analyze Speed Changes**:
- For sound waves:
- Speed increases when moving from water (rarer) to air (denser).
- For light waves:
- Speed decreases when moving from air (rarer) to water (denser).

5. **Analyze Wavelength Changes**:
- For sound waves:
- Wavelength increases as speed increases (λ increases).
- For light waves:
- Wavelength decreases as speed decreases (λ decreases).

6. **Analyze Frequency Changes**:
- For both sound and light waves:
- Frequency remains constant during reflection and refraction.

7. **Analyze Wave Number Changes**:
- For sound waves:
- Wave number (k) decreases as wavelength increases.
- For light waves:
- Wave number (k) increases as wavelength decreases.

8. **Determine Phase Changes**:
- For sound waves:
- The phase change for the reflected wave is zero.
- The phase change for the refracted wave is also zero.
- For light waves:
- The phase change for the reflected wave is π (180 degrees).
- The phase change for the refracted wave is zero.

### Summary of Changes in Physical Quantities

- **Sound Wave**:
- Speed: Increases (v3 > v1)
- Wavelength: Increases (λ3 > λ1)
- Frequency: Constant (f1 = f2 = f3)
- Wave number: Decreases (k3 < k1)
- Phase change (reflected): 0
- Phase change (refracted): 0

- **Light Wave**:
- Speed: Decreases (v3 < v1)
- Wavelength: Decreases (λ3 < λ1)
- Frequency: Constant (f1 = f2 = f3)
- Wave number: Increases (k3 > k1)
- Phase change (reflected): π
- Phase change (refracted): 0