Question

define evaporation. Explain.w hat are the affecting factors of evaporation and how they effect on the rate of evaporation

Answer 1

The phenomenon of change of liquid into vapours at any temperature below the boiling point of liquid is called evaporation. evaporation is also called as endothermic process.

(1) Amount of water available:

Rate of evaporation is greater over the oceans than over the continents.

(2) Temperature:
It is also affected by temperature. As the temperature of air is increased, its capacity to hold moisture also increases.

(3) Relative humidity:

The rate of evaporation is closely related with the relative humidity of air. Since the moisture holding capacity of air at a given temperature is limited, drier air evaporates more water than moist air.

(4) Wind-speed:

Evaporation depends on the wind speed as well. When the winds are light, a thin layer of air just above the surface gets nearly saturated; under the circumstances the difference between the vapour pressure between ground and air is very small.

(5) Area of the evaporating surface:

The rate of evaporation is determined by the area of the exposed surface of water. Larger areas of evaporating surface increase the rate of evaporation.

(6) Air-pressure:

Evaporation is also affected by the atmospheric pressure exerted on the evaporating surface. Lower pressure on open surface of the liquid results in the higher rate of evaporation.

(7) Composition of water:

Evaporation is inversely proportional to the salinity of water. Rate of evaporation is always greater over fresh water than over salt water. Under similar conditions, the ocean water evaporates about 5 per cent more slowly than the fresh water.

Answer 2

The phenomenon of change of liquid into vapours at any temperature below the boiling point of liquid is called evaporation. evaporation is also called as endothermic process. Factors affecting the rate of evaporation are: i) surface area - evaporation bein a surface area phenomenon, the rate of evaporation increases with increase in surface area. ii) temperature - the rate of evaporation increases with increase in temperature. iii) humidity - humidity is defined as the amount of water vapour present in the air. the rate of evaporation decreases. iv) wind speed - the rate of evaporation increases with increase in wind soeed. and increase in speed if wind causes water vapours particle to move away with the eind and this decreases the amount of water vapours in the surroundings. hope it helped you!!!