Atmospheric conditions are well governed by humidity. Which one among the following may best define humidity?

Humidity is fundamentally defined as the amount of water vapor or moisture content present in the atmosphere [4]. While water exists in the atmosphere in gaseous, liquid, and solid forms, the term humidity specifically refers to the gaseous water vapor [4]. It is a dynamic variable that changes based on time and location due to continuous exchange processes like evaporation and transpiration [4]. Options 1 and 3 describe forms of condensation, such as clouds, fog, or mist, which are visible aggregates of water droplets that form when air is cooled below its dew point [6]. Option 2 refers to precipitation or the settling of moisture. In contrast, humidity represents the invisible moisture content before it undergoes a phase change into liquid or solid forms [5]. Various measures like absolute and relative humidity quantify this moisture content relative to the air's capacity at specific temperatures [5].

Sources

1. [4] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 10: Water in the Atmosphere > EVAPORATION AND CONDENSATION > p. 87
2. [1] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 10: Water in the Atmosphere > CHAPTER > p. 86
3. [3] https://www.weather.gov/lmk/humidity
4. [6] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 24: Hydrological Cycle (Water Cycle) > Relative Humidity > p. 326
5. [5] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 14: Climate > TYPES OF PRECIPITATION > p. 136