21.The best unit duration of storm for a unit hydrograph is

22.Dimensions of coefficient of transmissibility are

23.The uplift pressure on the face of a drainage gallery in a dam is taken as

24.The rainfall on five successive days were measured as 100 mm, 80 mm, 60 mm, 40 mm and 20 mm respectively. If the infiltration index or the storm loss rate for the catchment area is earlier estimated as 50 mm/day, the total surface run off will be

25.When the upstream face of a gravity dam is vertical, then the intensity of water pressure at the water surface and at the base respectively will be