a) Rate of evaporation increases with an increase of surface area. 

Explanation:

1. During evaporation process, the particles escape from the surface of liquid. 

2. The increase in the surface area provides more scope for particles to escape from the surface.

3. Hence it leads to increase the rate of evaporation.

Ex: Water in a China dish evaporates faster than the water in test tube.

b) Rate of evaporation decreases with the increase in humidity.

Explanation:

1. The amount of water present in air is called humidity. 

2. The air around us cannot hold more than a definite amount of water vapour at a given temperature.

3. If the amount of water vapour is high in air, then the rate of evaporation decreases. 

Ex : Clothes dry slowly on a rainy day than on a normal day.

c) Rate of evaporation increases with the increase in wind speed.

Explanation:

1. Because of increase in wind speed, particles of water vapour move away with the wind. 

2. Due to this, amount of water vapour in the surroundings decreases. 

3. It leads to increase in the rate of evaporation. 

Ex: Clothes dry faster on a windy day or under fan than a normal day.