Define relative humidity . OR
What is relative humidity ?
Write the formula for % relative humidity .

Explanation

### Step-by-Step Solution:

1. **Definition of Relative Humidity**:
Relative humidity is a measure of the amount of water vapor present in the air compared to the maximum amount of water vapor that the air can hold at a given temperature. It is expressed as a percentage.

2. **Understanding the Concept**:
- The air can hold varying amounts of water vapor depending on its temperature.
- Relative humidity indicates how close the air is to being saturated with moisture.
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