Water table drops by 3 m in an irrigable land of 50 hectare. If porosity and specific retention are 0.30 and 0.10 respectively, the change in storage in hectare-meter is :
3. Effective length of a column effectively held in position and restrained in direction at one end but neither held in position nor restrained in direction at the other end, is
10. If x% is the gradient of an alignment and y% is the gradient after proper superelevation along a curved portion of a highway, the differential grade along the curve, is