Water is coming out from a tap and falls vertically downwards. At the tap opening the stream diameter is 20 mm with uniform velocity of 2 m/s. acceleration due to gravity is 9.81 m/s2. Assuming steady, inviscid flow, constant atmospheric pressure everywhere and neglecting curvature and surface tension effects, the diameter in mm of the stream 0.5 m below the tap is approximately.
(a) 10 (b) 15
(c) 20 (d) 25