Which of the following statements are correct?

Options

A. Changes inair temperature have no effect on the speed of sound.
B. Changes in air pressure have no effect on the speed of sound.
C. The speed of sound in water is higher that in air.
D. The speed of sound in water is lower than in air.

Explanation

To determine which statements about the speed of sound are correct, let's analyze each statement one by one based on the principles of sound waves.

### Step-by-Step Solution:

1. **Understanding the Speed of Sound Formula**:
The speed of sound in a medium can be expressed as:
\[ v = \sqrt{\frac{\gamma P}{\rho}} \]
where \( v \) is the speed of sound, \( \gamma \) is the adiabatic index (ratio of specific heats), \( P \) is the pressure, and \( \rho \) is the density of the medium.

2. **Analyzing Statement 1**: "Change in air temperature has no effect on speed of sound."
- **Explanation**: This statement is incorrect. The speed of sound in air is affected by temperature because an increase in temperature decreases the density of air, which can increase the speed of sound. Thus, temperature changes do affect the speed of sound.

3. **Analyzing Statement 2**: "Change in air pressure has no effect on speed of sound."
- **Explanation**: This statement is also incorrect. The speed of sound is directly related to pressure. An increase in pressure (at constant temperature) leads to an increase in the speed of sound because it increases the density of the medium. Therefore, changes in pressure do affect the speed of sound.

4. **Analyzing Statement 3**: "Speed of sound in water is higher than in air."
- **Explanation**: This statement is correct. The speed of sound in water is significantly higher than in air due to the higher density and incompressibility of water compared to air. Thus, sound travels faster in water.

5. **Analyzing Statement 4**: "Speed of sound in water is lower than in air."
- **Explanation**: This statement is incorrect. As established in the previous analysis, the speed of sound in water is higher than in air.

### Conclusion:
Based on the analysis, the only correct statement is:
- **C**: "Speed of sound in water is higher than in air."

### Final Answer:
The correct statement is C.

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