A permeameter of diameter 84 mm contains a column of fine sand 500 mm long. When water flows through it under a constant head at a rate of 200 ml/minute, the loss of head between two points 250 mm apart is 360 mm, (i) Calculate the coefficient of permeability. (ii)If the falling head test is performed of diameter 40 mm, how long will the water level in the standpipe fall from 1660mm to 1100 mm above the outflow level