Relative humidity is the percentage of the

Options

A. absolute humidity value to the amount of humidity actually present
B. increase of humidity/absolute humidity
C. amount of humidity actually present to the absolute humidity
D. none of these

Answer

### Step-by-Step Solution:

1. **Understanding Humidity**:
- Humidity refers to the amount of water vapor present in the air. It is an important factor in weather and climate.

2. **Defining Relative Humidity**:
- Relative humidity is a specific measure of humidity. It indicates how much water vapor is currently in the air compared to the maximum amount of water vapor the air can hold at a given temperature.

3. **Formula for Relative Humidity**:
- The formula for calculating relative humidity (RH) is:
\[ \text{Relative Humidity (RH)} = \left( \frac{\text{Actual Vapor Density}}{\text{Saturation Vapor Density}} \right) \times 100\% \]
- Here, Actual Vapor Density is the amount of water vapor present in the air, and Saturation Vapor Density is the maximum amount of water vapor that the air can hold at that temperature.

4. **Interpreting Relative Humidity**:
- Relative humidity is expressed as a percentage. A relative humidity of 100% means the air is fully saturated with water vapor and cannot hold any more, leading to the possibility of condensation (like dew or rain).

5. **Conclusion**:
- Therefore, relative humidity is the percentage of the actual amount of humidity present in the air compared to the maximum (absolute) humidity that the air can hold at a specific temperature.

### Final Answer:
Relative humidity is the percentage of the amount of humidity actually present to the absolute humidity.