Speed of sound waves in air a) is independent of temperature b) increases with pressure c) increases with increase in humidity d) decreases with increase in humidity.

Options

A. is independent of temperature
B. increases with pressure
C. increases with increase in humidity
D. decreases with increase in humidity.

Explanation

To determine the correct statement regarding the speed of sound waves in air, let's analyze each option step by step.

### Step 1: Understanding the relationship between speed of sound and temperature
- The speed of sound in air is affected by temperature. As the temperature increases, the speed of sound also increases. This is because warmer air has more energy, allowing sound waves to travel faster.
- **Conclusion**: Option (a) is incorrect.

### Step 2: Analyzing the effect of pressure on speed of sound
- The speed of sound in air is primarily affected by temperature and density rather than pressure. In an ideal gas, if the temperature is constant, increasing the pressure does not significantly affect the speed of sound because both density and pressure increase proportionally.
- **Conclusion**: Option (b) is incorrect.

### Step 3: Investigating the effect of humidity on speed of sound
- Humidity refers to the amount of water vapor present in the air. When humidity increases, the density of air decreases because water vapor is less dense than the nitrogen and oxygen that make up most of the air.
- Since the speed of sound is inversely proportional to the square root of the density, a decrease in density (due to increased humidity) results in an increase in the speed of sound.
- **Conclusion**: Option (c) is correct.

### Step 4: Evaluating the last option regarding humidity
- Since we established that the speed of sound increases with increased humidity, it contradicts option (d), which states that the speed decreases with increased humidity.
- **Conclusion**: Option (d) is incorrect.

### Final Answer
The correct option is **(c) increases with increase in humidity**.

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