21.Which of the following types of rain gauges is used for measuring rain in remote hilly inaccessible areas ?

22.The "outlet discharge factor" is the duty at the head of

23.Rate of evaporation from a water surface increases if i) difference of vapour pressure between water and air is increased ii) velocity of wind is decreased iii) concentration of soluble solids in water is decreased The correct answer is

24.The amount of irrigation water required to meet the evapotranspiration needs of the crop during its full growth is called

25.The water utilizable by plants is available in soils mainly in the form of