109) The most economical section of a trapezoidal channel is one which has hydraulic mean depth equal to

110) A flow is called sub-sonic, if the Mach number is

111) The discharge of a depressed nappe is 6 to 7 percent __________ that of a free nappe.

112) Re-entrant or Borda's mouthpiece is an __________ mouthpiece.

113) The flow in a pipe is neither laminar nor turbulent when Reynold number is